Sidney Cywes was born in South Africa in the town of Paarl in the Western Cape on 1 January 1931. He studied medicine at the University of Cape Town (UCT) and graduated MB, ChB in 1953. He trained at the Red Cross War Memorial Children’s Hospital (RCWMCH) and worked there throughout his career. In 1961 he became a lecturer in surgery at UCT and eventually, in 1975, he was appointed to the newly created Charles F. M. Saint chair of paediatric surgery. Throughout his career he published widely in professional journals and edited several books. Particularly interested in complex surgical problems, among the topics he covered were the separation of conjoined twins, Hirschsprung’s disease, ano-rectal malformations, surgical oncology, oesophageal replacement and organ transplantation. At the RCWMCH he was responsible for many important innovations in his field. As the first surgeon in South Africa to concentrate entirely on paediatric surgery, he was well aware of children’s needs. Under his influence the hospital developed a neonatal surgery unit in 1976, a day surgery service from 1976 with its own centre from 1989, a trauma unit in 1984 and a liver transplantation programme. He also helped found the Child Accident Prevention Foundation of Southern Africa in 1978, which provided a child safety centre at his hospital and has now been in existence for 40 years. Internationally he was extremely active and his reputation meant that he was awarded the honorary fellowship of many important surgical colleges. In his own particular field, he was past president of the World Federation of Associations of Paediatric Surgeons, founding member and president of the South African Association of Paediatric Surgeons, honorary life member of the British Association of Paediatric Surgeons and helped establish the Pan African Association of Paediatric Surgeons. Outside medicine he and his wife, Marlene, were experts in horticulture. They won competitions in the growing of dahlias, roses and orchids, and became known as two of South Africa’s foremost gardeners. He died on 6 April 2020 aged 89 and was survived by his wife and children, Robert and Colette.