The South Australian population of approximately 1,245,000 is 9.2% of the total Australian population. The Cardio-Thoracic Surgical Unit of the Royal Adelaide Hospital is the only one such unit in the State which is equipped for open heart surgery, and coronary artery grafting was first undertaken there in December, 1970. From that time until the end of December, 1976, 701 patients underwent coronary artery grafting with an overall hospital mortality of 3.0%, and a late mortality of 3.2%. The principal indication for operation was incapacitating angina, and of the 628 patients who have been followed-up after operation for a minimum period of six months, 78.6% were judged by their cardiologist to be completely relieved of this symptom. A further 8.9% of patients were considered to be significantly improved. Coronary artery surgery has rapidly assumed a dominant role in our Unit so that, in 1976, of the 435 open heart operations which were performed, 267 (61%) were procedures which necessitated coronary artery grafting. The rate of increase has slowed considerably over the past 18 months, and it is expected that, with current operative indications, the proportion of coronary artery cases will not rise much above 60% of the open heart work load of the Unit.