Bachelor of Medicine, Bachelor of Surgery, or in Latin: Medicinae Baccalaureus Baccalaureus Chirurgiae (abbreviated in many ways, e.g. MBBS, MB ChB, MB BCh, MB BChir (Cantab), BM BCh (Oxon), BMBS), are the two first-professional degrees in medicine and surgery awarded upon graduation from medical school by universities in countries that follow the tradition of the United Kingdom. The historical degree nomenclature states that they are two separate undergraduate degrees; however, in practice, they are usually combined as one and conferred together, and may also be awarded at graduate-level medical schools. In countries that follow the tradition of continental Europe or the system in the United States, the equivalent medical degree is awarded as Doctor of Medicine (MD) or Doctor of Osteopathic Medicine (DO) — the latter in the United States only.

The names and abbreviations given to these degrees depend on the institution, awarding body or country, and vary widely. This is mostly for reasons of tradition rather than to indicate any difference between the relative levels of the degrees. They are considered equivalent.

If the awarding body titles the degrees in Latin, the degrees are commonly named Medicinae Baccalaureus, Chirurgiae Baccalaureus; Medicinae Baccalaureus et Chirurgiae Baccalaureus; or Baccalaureus in Medicina et in Chirurgia; abbreviated as MB ChB, MB BCh or otherwise. If titled in English, they are named Bachelor of Medicine, Bachelor of Surgery; Bachelor of Medicine and Bachelor of Surgery; or Bachelor of Medicine and Surgery; usually abbreviated as MB BS, and sometimes as BM BS, even though most MB BS-awarding institutions do not use Latin to name their degrees.

The degree is currently awarded in institutions in Australia, Bahrain, Bangladesh, Barbados, Botswana, Brazil, Colombia, China, Egypt, Fiji, Gambia, Ghana, Guyana, Hong Kong, India, Iraq, Ireland, Jamaica, Jordan, Kenya, Kuwait, Lebanon, Libya, Malawi, Malaysia, Mauritius, Myanmar, Namibia, Nepal, New Zealand, Nigeria, Pakistan, Papua New Guinea, Philippines, Samoa, Saint Kitts and Nevis, Saudi Arabia, Sierra Leone, Singapore, South Africa, Malaysia, Sri Lanka, Sudan, Tanzania, Trinidad and Tobago, Uganda, Ukraine, the United Arab Emirates, the United Kingdom, Vanuatu, Zambia and Zimbabwe.

Historically, Bachelor of Medicine was also the primary medical degree conferred by institutions in the United States and Canada, such as the University of Pennsylvania, Harvard, the University of Toronto, the University of Maryland, and Columbia. Several early North American medical schools were (for the most part) founded by physicians and surgeons who had trained in England and Scotland. University medical education in England culminated with the Bachelor of Medicine qualification and in Scotland the Doctor of Medicine. In the mid-19th century, the public bodies that regulated medical practice required practitioners in Scotland and England to hold the dual Bachelor of Medicine and Bachelor of Surgery degrees. Throughout the 19th century, North American medical schools switched to the tradition of the ancient universities of Scotland and began conferring Doctor of Medicine rather than Bachelor of Medicine.

In the countries that award bachelor’s degrees in medicine, however, Doctor of Medicine denotes a holder of a junior doctorate and is reserved for medical practitioners who undertake research and submit a thesis in the field of medicine. Nevertheless, those holding Bachelor of Medicine, Bachelor of Surgery are usually referred to by the courtesy title of “Doctor” and use the prefix “Dr.”, whether or not they also hold a PhD or DSc. In theory, the right to the use of the title “Doctor” is conferred on the medical graduate when he or she is registered as a medical practitioner by the relevant professional body, not by the possession of the MBBS degrees. The reason is found in a parallel tradition for those who are post-graduate specialists in surgery: on acceptance into a College of Surgeons, they stop styling themselves “Doctor” and revert to “Mister” (Mr), “Miss”, “Muz” (Ms) or “Missus” (Mrs). This curious situation, where an elevation in professional rank is signified by dropping the title of Doctor, came about because historically a “surgeon” was an ordinary worker, usually a barber, not trained in medicine but performing dissections and surgery under the direction of a gowned academic who was the actual “doctor”.

Despite their styling as two degrees, Bachelor of Medicine and Bachelor of Surgery are usually conferred together. At some institutions, such as Oxford and Cambridge, it was possible to be awarded the degrees in different years.[citation needed]

In many countries, the degrees are awarded after an undergraduate course lasting five or six years. For example, most Chinese universities offering medical degrees provide undergraduate courses lasting six years. In some cases, a graduate in another discipline may subsequently enter a special graduate-entry medical course, reduced in duration to account for relevant material covered or learning skills acquired during the first degree. In some cases the old first-year courses (for six-year degrees) in the basic sciences of physics, chemistry and biology have been abolished: that standard has to be reached by school examinations before entry. However, in most countries, a newly graduated Bachelor of Medicine and Surgery must spend a specified period in an internship before they can obtain full registration as a licensed medical practitioner.

Recently, courses have been established in the Commonwealth country Australia that awards the title MD.