The Medical and Chirurgical Society of London was a learned society of physicians and surgeons which was founded in 1805 by 26 personalities in these fields who had left the Medical Society of London (founded 1773) because of disagreement with the autocratic style of its president, James Sims. Among its founders there were William Saunders (1743–1817), its first president; John Yelloly (1774–1842), Sir Astley Cooper (1768–1841), the first treasurer; Alexander Marcet (1770–1822) and Peter Mark Roget (1779–1869).
According to its charter, the Medical and Chirurgical Society of London was founded "for the purpose of conversation on professional subjects, for the reception of communications and for the formation of a library" and served "several branches of the medical profession".
In 1834 the Society received a Royal charter, thus becoming the Royal Medical and Chirurgical Society of London. This society merged with several other specialist societies, from 1907 to 1909, to form the current Royal Society of Medicine.
The 17 societies which merged with the Medical and Chirurgical Society to form the Royal Society of Medicine were:
Honorary Fellows of the society included luminaries such as Charles Darwin, Louis Pasteur, Edward Jenner and Sigmund Freud. Other presidents of note were the "three great from Guy's Hospital", Richard Bright (1837); Thomas Addison (1849) and Sir James Paget (1875), as well as Joseph Hodgson (1851) and Frederick William Pavy (1900).