Olga Jonasson was professor of surgery at the University of Illinois at Chicago and a pioneer in organ transplantation. Born in Peoria, Illinois, the daughter of a Swedish Lutheran pastor and a nurse, she was first attracted to medicine by following her father round on his hospital visits. After Lyman Trumbull Elementary School and North Park Academy, she attended Northwestern University as an undergraduate, and won honours for her MD from the University of Illinois, a tough medical school whose practice included the notorious Cook County Hospital. She did her residency under Warren Cole at the Illinois Research and Education Hospital at a time when the department was devoted to the hunt for cancer cells in the venous blood draining cancers, many of those being actually monocytes. Exceptionally tall and blonde, she stood out from her fellow residents for her fearless and outspoken criticism of her peers and her seniors. After her residency Olga did a fellowship in immunochemistry at the Walter Reed Army Institute of Research, which was followed by a second fellowship in transplantation immunology at the Massachusetts General Hospital. In 1969 she did the first renal transplant in Illinois. She was one of the first to realise the importance of HLA (human leukocyte antigen) matching, setting up a nationwide matching scheme. In 1967 she became chairman of the department of surgery at Ohio State University College of Medicine, the first woman in the United States to become head of a department of surgery. She served as director of education and surgical services at the American College of Surgery from 1993 to 2004. Her interests were not limited to transplantation: she studied inguinal hernia, pointed out that watchful waiting was appropriate in many cases, and carried out clinical trials comparing open versus laparoscopic repair. She was also a determined advocate of helmets for motorcycle riders. Despite having a formidable reputation as an ‘ice queen’, she was highly regarded by her peers, and went out of her way to encourage young women to take up careers in surgery, although she warned them not to marry or, if married, to get divorced. However, this did not stop her from being a sympathetic friend to them and their spouses. She was involved in the Episcopal Church of the Epiphany, Chicago, raising huge sums of money to repair its fabric, and was an expert cook and a lover of opera. She was made an honorary FRCS in 1988. She died on 30 August 2006.