Catherine Lewis, a consultant general and urological surgeon in London, was the second woman to become a fellow of the Royal College of Surgeons of England and one of the first female members, and a founding member, of the British Association of Urological Surgeons (BAUS). She was born in London on 29 May 1882. Her father, James Lewis, a paymaster in the Royal Navy, died in 1885 when she was a very young child; her mother was Emily Catherine Lewis née Wooldridge, who was from a Naval family. According to Lewis’ obituary in *The Lancet*, she spent her early years in Cornwall and was then taken to Germany by her mother, where she studied music. Her older brother from her mother’s first marriage, John Anthony Hawke, became a judge and the Conservative MP for St Ives and was knighted in 1928. When her mother died in 1906, Lewis went to live with Edward Drummond Hay Hawke, another of her mother’s sons from her first marriage, who had studied medicine at Charing Cross Hospital and was a physician at Shortlands in Kent. Perhaps influenced by her half-brother’s choice of career, in her late twenties Lewis gave up a successful teaching career in music and enrolled at the London School of Medicine for Women. She qualified with the conjoint diploma in 1917 at the age of 35 and gained her MB BS from London University with honours a year later. In 1919 she became only the second woman to gain the FRCS, eight years after Eleanor Davis-Colley became the first female fellow. In 1920 Lewis gained her master of surgery degree. She held house appointments at Charing Cross Hospital, the Hospital for Women in Soho Square and the Royal Free Hospital. In 1920 she was appointed as a surgeon to the Royal Free Hospital and the South London Hospital for Women. She later also joined the staff of the Marie Curie Hospital. At the Royal Free she was also an assistant lecturer and senior demonstrator in anatomy and then a lecturer. She was one of the first female general surgeons at a London teaching hospital. She also became interested in the surgery of the female urinary system, despite being told by colleagues that there was no money in the specialty. She honed her urological skills at St Peter’s Hospital for the Stone, where she was a clinical assistant to Clifford Morson: at the Royal Free she founded the department of urology. Her book *Urology in women. A handbook of urinary diseases in the female sex* (London, Baillière & Co, 1932; second edition 1936) was a pioneering text on the subject. She published papers on urological topics in the *Postgraduate Medical Journal*, *The Lancet*, the *British Journal of Urology* and *Medical World*. In 1945, when the BAUS was established, Lewis became one of two female founding members, along with Helen Wingate, a surgeon from Glasgow. During the Second World War Lewis served in the Royal Free sector of the Emergency Medical Service, operating through the Blitz in London and at Arlesey in Bedfordshire. After the war she retired to Ely in Cambridgeshire. In her retirement she studied precious stones and continued her interest in music. Lewis died in the Royal Free Hospital in London on 25 October 1965 of an obstruction secondary to bowel cancer. She was 83. Considered a sound surgical opinion and an excellent teacher by colleagues, with a meticulous operative skill, she was described as shy and reserved. She never married but had a close circle of friends. One commented in her *Lancet* obituary: ‘She was a charming hostess: her elegant manners and subtle sense of humour were a continual joy.’