Doctor of Medicine (MD, from the Latin Medicinæ Doctor meaning "Teacher of Medicine") is a doctoral degree for physicians. The degree is granted by medical schools. It is a professional doctorate / first professional degree (qualifying degree) in some countries, including the United States and Canada, although training is entered after obtaining from 90 to 120 credit hours of university level work (see second entry degree) and in most cases after having obtained a Bachelors Degree. In other countries, such as India, the United Kingdom, Germany, and Sri Lanka, the MD is an advanced academic research degree similar to a PhD or a higher doctorate. In India, Britain, Ireland, and many Commonwealth nations, the medical degree is instead the MBBS i.e. Bachelor of Medicine, Bachelor of Surgery (MBChB, BM BCh, MB BCh, MBBS, BMBS, BMed, BM) and is equivalent to the MD and DO degrees in the U.S. system.
According to Sir John Bagot Glubb, Syed Faride and S. M. Imamuddin, the first medical schools to issue academic degrees and diplomas were the teaching Bimaristan (Hospitals) of the medieval Islamic world. The first of these institutions was opened in Baghdad during the time of Harun al-Rashid. They then appeared in Egypt from 872 and then in Islamic Spain, Persia and the Maghreb thereafter. Physicians and surgeons at these hospital-universities gave lectures on Medicine to medical students and then a medical diploma or degree was issued to students who were qualified to be practicing physicians.
According to Douglas Guthrie, who bases his account on L Thorndike, medical men were first called "Doctor" at the Medical School of Salerno. He states that the Emperor Frederick II decreed in 1221 that no one should practice medicine until he had been publicly examined and approved by the masters of Salerno. The course lasted 5 years, and to start one had to be 21 years old and show proof of legitimacy and of three years study of logic. The course was followed by a year of supervised practice. After the laureation ceremony the practitioners could call themselves "magister" or "doctor."
The first medical schools that granted the MD degree were Columbia, Penn, Harvard, Maryland, and McGill  These first few North American medical schools that were established were (for the most part) founded by physicians and surgeons who had been trained in England and Scotland. University medical education in England culminated with the MB qualification, and in Scotland the MD, until in the mid-19th century the public bodies who regulated medical practice at the time required practitioners in Scotland as well as England to hold the dual Bachelor of Medicine and Bachelor of Surgery degrees (MB BS/MBChB/MB BChir/BM BCh etc.). North American Medical schools switched to the tradition of the Ancient universities of Scotland and began granting the M.D. title rather than the MB beginning in the late 18th century. The Columbia University College of Physicians and Surgeons in New York (which at the time was referred to as King's College of Medicine) was the first American University to grant the MD degree instead of the MB.
In the United States, MDs are awarded by medical schools accredited by the Liaison Committee on Medical Education (LCME), an independent body sponsored by the Association of American Medical Colleges and the American Medical Association (AMA). 
Admission to medical schools in the United States is highly competitive, with about 17,800 out of approximately 47,000 applicants receiving at least one acceptance to any medical school in recent application years. Before entering medical school, students must complete a four year undergraduate degree and take the Medical College Admission Test (MCAT). Before graduating from a medical school and achieving the degree of Medical Doctor, most schools require their students to take the United States Medical Licensing Examination (USMLE) Step 1 and both the Clinical Knowledge and Clinical Skills parts of Step 2. The M.D. degree is typically earned in four years. Following the awarding of the MD, physicians who wish to practice in the United States are required to complete at least one internship year (PGY-1) and pass the USMLE Step 3. In order to receive Board Eligible or Board Accredited status in a specialty of medicine such as general surgery or internal medicine, then undergo additional specialized training in the form of a residency. Those who wish to further specialize in areas such as cardiology or interventional radiology then complete a fellowship. Depending upon the physician's chosen field, residencies and fellowships involve an additional three to eight years of training after obtaining the M.D. This can be lengthened with additional research years, which can last one, two, or more years. The Doctor of Osteopathic Medicine or D.O. degree is the only other legal and professional equivalent to the M.D. degree in the United States and some parts of Canada. The differences between the M.D. and the DO degrees lie in the distinctive osteopathic philosophy and osteopathic manipulative treatment (OMT). In Canada, the M.D. is the basic medical degree required to practice medicine. McGill University Faculty of Medicine is the only medical school in Canada to award M.D., C.M. degrees (abbreviated MDCM). MDCM is from the Latin "Doctorem Medicinae et Chirurgiae Magistrum" meaning "Doctor of Medicine and Master of Surgery".
Even though the M.D. / D.O. is a first professional degree and not a doctorate of research (i.e. Ph.D.), many holders of the M.D. or D.O. degree conduct clinical and basic scientific research and publish in peer-reviewed journals during training and after graduation. Combined medical and research training is offered through programs granting MD/PhD or DO/PhD degrees. The National Institutes of Health through its Medical Scientist Training Program funds MD/PhD training programs at many universities. Some MDs and DOs choose a research career and receive funding from the NIH as well as other sources such as the Howard Hughes Medical Institute. A few even go on to become Nobel Laureates. The United States Department of Education and the National Science Foundation do not include the M.D. or other professional doctorates among the degrees that are equivalent to research doctorates.
In the UK, Ireland and many Commonwealth countries, the MD is a postgraduate research degree in medicine. At some universities, this takes the form of a first doctorate, analogous to the PhD, awarded upon submission of a thesis and a successful viva. The thesis may consist of new research undertaken on a full- or part-time basis, with much less supervision (in the UK) than for a PhD, or a portfolio of previously published work.
In order to be eligible to apply for an MD degree from a UK or Commonwealth University one must hold either an MBBS, MBChB, or an equivalent US-MD degree and must usually have at least 5-years of postgraduate experience. Therefore graduates from the MBBS or MBChB degrees do not hold doctorates, however physicians holding these degrees are referred to as 'Doctor' as they are fully licensed as primary care physicians upon the completion of mandatory clinical internship minimum of one full year after graduating from the medical college. In some commonwealth nations these interns are designated as as House surgeons. Total duration to obtain MBBS degree is about 6 years that includes 5 years of course work and minimum one year of Compulsory rotating clinical internship.
At some other universities (especially older institutions such as Oxford, Cambridge and St Andrews) the MD is a higher doctorate (similar to a DSc) awarded upon submission of a portfolio of published work representing a substantial contribution to medical research.
In the case where the MD is awarded (either as a first or higher doctorate) for previously published research, the candidate is usually required to be either a graduate or a full-time member of staff, of several years' standing of the university in question.
The entry-level first professional degree in these countries for the practice of medicine is that of Bachelor of Medicine and Bachelor of Surgery (MBBS, MB, MB BCh BAO, BMBS, MBBChir, or MBChB). This degree typically requires between four and six years of study and clinical training, and is equivalent to the North American MD degree.
The University of Melbourne in Australia introduced the North American MD degree in 2011 for graduates of the Bachelor of Biomedicine and Bachelor of Science New Generation degrees. The university is the first in Australia to leave the Bachelor of Medicine and Bachelor of Surgery (MBBS) and offer the MD as a first professional degree in medicine rather than as a research degree. The first cohort of MD students from the university will graduate in 2014, one year after the last graduating cohort of MBBS students. The University of Melbourne renamed its previous research MD degree to Doctor of Medical Science (DMedSc), which will distinguish the new MD graduates from the doctors who obtain the research degree.
The University of Western Australia from 2014 will begin a similar 4 year post graduate course with graduates qualifying with an MD rather than the MBBS as it stood up until 2011.
In Argentina the First Degree of Physician or Medic Title (Título de Médico) is equivalent to the North American M. D. Degree with 6 year of intensive studies followed by usually three or four years of the residency as a major specialty in a particular empiric field, compounded of internships, social services and sporadic research. Only by holding a Medical Title the postgraduate student might apply for the Doctor degree through a Doctorate in Medicine program approved by the National Commission for University Evaluation and Accreditation.
The MBBS degree represents the first (graduation) level of training required to be licensed as a physicians, and the MD degree is a higher postgraduate degree, representative of specialty training. The equivalent training in the US or Canada would be completion of a medical (post-graduate) degree. Eligibility for the MD course is restricted to medical graduates holding the MBBS degree. The MBBS course is for five and a half years, and training is obtained in medical disciplines (e.g.: Internal Medicine, Radiology, Pathology, etc.). After three years of study and the successful completion of an examination, which includes both theoretical and practical elements, in a pre-clinical or clinical subject of a non-surgical nature, the candidate receives an MD degree.
The research element is not prominent in India, as this is primarily a clinical qualification resembling the professional doctorates of the USA. In general surgery, orthopaedics and gynaecology the equivalent degree is Master of Surgery (MS).
A third qualification, termed DNB [Diplomate of National Board], is considered equivalent to the MD and MS degrees. This can be obtained by passing the exam conducted by the National Board of Examinations after completing 3 years of post-MBBS residency training in teaching hospitals recognised by the board.
After obtaining the first postgraduate degree, that is MD/MS/DNB, one can go for further specialisation in medical or surgical fields. This requires three years of additional training and study and then passing an examination, both theory and practical, and the degree awarded is DM (Doctor of Medicine), like DM in Cardiology, Neurology, Nephrology, Gastroenterology, etc. For surgical subspecialities the degree awarded is MCh (Magister Chirurgiae), like MCh in Cardiac thoracicSurgery, Neurosurgery, etc. A third qualification in subspecialities is DNB (superspecialties), offered by National Board of Examinations, like DNB in Cardiology, Neurology, Cardiac Surgery, Neurosurgery, etc.
The MCh degrees are for super-specialties in medicine and are very high ranked/prestigious.
In Ayurveda, B.A.M.S in Unani, Bachelor of Unani Medicine and Surgery BUMS in Sidha BSMS in homoeo B.H.M.S are the basic qualification for practicing Ayurveda,Unani,Homoeo&Sidha. The B.A.M.S, B.U.M.S, B.S.M.S and B.H.M.S are 6 year degree (including internship called house surgeoncy) course after 12 years of formal education at a C.C.I.M approved colleges. M.D has to be done after B.A.M.S, B.U.M.S, B.S.M.S or B.H.M.S in a speciality, and it takes 3 years (including submission of a thesis) to complete the course. In Acupuncture Diploma in Acupuncture D Acu is the basement course for Bachelor of Acupuncture B Acu (three years). MD Acu is the post graduate(Master)degree in Acupuncture(two years after B Acu).
In Pakistan equivalent degree is MBBS (bachelors of medicine and bachelors of surgery). MBBS is awarded as the basic medical qualification after completing five years of study. This comprises two years of basic science subjects including anatomy, physiology, and biochemistry, with a particular emphasis on human anatomy. Subsequently, there are three years of clinical internship and courses on medicine surgery and pharmacology. Finally, the student is required to work for one year under a professor, before one is awarded Degree of MBBS with license to practice. For specialization, one has to pass Fellow of College of Physicians & Surgeons Pakistan (FCPS) exam-1 in field in of specialization and obtain an internship in the field for 3–6 years. Next, one can take the FCPS exam part 2, which includes intensive practical exams. Upon successful completion a fellow of the relevant specialty is awarded. Tough entry tests are passed successfully before entering in to a medical college. Medical colleges and foreign medical qualifications are supervised by the Pakistan Medical and Dental Council (PMDC). Specialized degrees are awarded by the Pakistan College of Physicians and Surgeons.In basic medical sciences such as Anatomy, Physiology, Biochemistry, Pathology etc. the research postgraduate degree awarded by many universities is M.Phil., which has a pre-requirement of at least two years of Demonstratorship in relevant subject in a recognized Medical College. The Mphil course is 2–4 years and is a research postgraduate degree, containing submission and defence of research thesis in basic sciences similar to MD degree program in India.Many universities in conjunction with tertiary hospitals offer coursework MD and MS degrees as well.
Romanian medical school lasts for 6 years including clinical practice and concludes with a final licensing examination (licenta). The degree awarded is Doctor-medic (Medical Doctor) abbreviated as MD.
In Sri Lanka, MBBS degree is the degree to be held for one to be licensed as a physicians by the Sri Lanka Medical Council. MD degree is a higher postgraduate degree and in Sri Lanka awarded by the Postgraduate Institute of Medicine after completion of a postgraduate course and examinations. The MD degree in Sri Lanka is representative of specialty training in clinical, para clinical and preventive medicine (e.g. General Medicine, Cardiology, Nephrology, Oncology, para clincal such as microbiology, haematology and preventive such as Community Medicne .). Entry for the MD course open only for medical graduates holding the MBBS degree (with a duration of five and a half years), and training is obtained in medical disciplines that are non-surgical in nature (e.g. Internal Medicine, Radiology, Pathology, etc.). After three or four years of study and the successful completion of an examination with written as well as cases and viva examinations, the MD degree in the respective field of Study is awarded. In Community medicine and Medical Administration, part I examination consists of a theoretical exam while the degree is cofered after completion of a thesis as n PhD. This thesis has to be completed within a period of five years. After successfully defending the academic thesis, MD degree is conferred to the candidate,The MD degree holder is certified as a Board certified specialist by the respective board of study of the Postgraduate Institute of Medicine after he/she undergoes 2–4 years of local and foreign training depending on the specialty/subspecialty selected.
There is also a similar advanced professional degree to the postgraduate MD: the Master of Surgery (usually ChM or MS, but MCh in Scotland, Ireland, Wales and at Oxford and MChir at Cambridge). The equivalence of these degrees, but their differing names, prevents the need for surgeons (addressed as Mr. in the UK) having to revert to the title Dr., which they once held as new MBBS graduates.
In Ireland, where the basic medical qualification includes a degree in obstetrics, there is a similar higher degree of Master of the Art of Obstetrics (MAO). A Master of Midwifery was formerly examined by the Worshipful Society of Apothecaries of London (hence MMSA) but fell into abeyance in the 1960s; in this case the term Master referred not to a university degree but rather a professional rank that is common among craft guilds.
In East Africa, the medical schools in Kenya, Tanzania and Uganda award the degree of Master of Medicine (MMed) degree in both surgical and medical specialty disciplines following a three year period of instruction.
In West Africa, the West African College of Physicians and the West African College of Surgeons award the Fellowship of the West African College of Physicians (FWACP) and the Fellowship of the West African College of Surgeons (FWACS) in medical and surgical disciplines respectively after a minimum of four year residency training period.