During the period 1963-1982 a total of 11,459 patients with general surgical and thoracic conditions were admitted to the Churchill and John Radcliffe Hospitals in Oxford under the care of a single thoracic surgeon. 55.1% of the admissions were for general surgical conditions whereas 44.9% were for a thoracic disorder. The total period has been studied by dividing it into three subgroups of 7, 6 and 7 years (1963-1969, 1970-1975, 1976-1982). The percentage of thoracic patients treated during the three periods was found to be 48.86%, 41.73% and 50.11% respectively. The three periods studied have been subdivided into major disease groups and the changes in these groups have been studied in detail. During this 20-year period there has been a dramatic change in the makeup of a typical thoracic surgical practice. This is in part due to the changing pattern and prevalence of many of the diseases treated by thoracic surgeons, but is also due to a change in referral patterns, the distribution of patients between thoracic and general surgeons and also the dichotomy emerging between thoracic and cardiac surgeons.