A retrospective analysis was made of the case records of 1568 surgical patients admitted in 1975 to a tertiary care hospital in the Province of Newfoundland, to determine and classify the incidence of concurrent systemic disease. Almost 60 percent of patients had symptoms or signs of concurrent disease, the numbers increasing progressively from below 30 per cent at 21-30 years, to 90 per cent at ages 71-80. The predominant abnormalities were cardiovascular (60 per cent), followed by respiratory and metabolic conditions (41 and 40 per cent respectively).Detailed findings are presented, including those relating to the incidence ofischaemic heart disease and hypertension, to the coexistence of several diseases, to smoking and chronic obstructive lung disease, to obesity, to diabetes, and to alcoholism. This review documents the high incidence of concurrent disease in surgical patients and has implications for the training of anaesthetists and the organization of their work.KEY WORDS: SURGERY~ concurrent disease; COMPLICATIONS~ concurrent disease.THE INCIDENCE of concurrent systemic disease in surgical patients has obvious relevance to the work and staffing of departments of anaesthesia, and to the training and responsibilities of anaesthetists. There have been several reports relating to British hospitals, but little information from North America. We believe that it is of interest to analyze and document this aspect of anaesthetic practice, and we present here our report from 1568 unselected surgical patients treated in 1975 in a tertiary care hospital serving the Province of Newfoundland and Labrador. METHODSSurgical case records from the year 1975 were extracted randomly from the files by a staff member of the Department of Medical Records, and were then reviewed by one of us (R.W.). The 1568 cases analyzed were a large and unselected sample representative of the 5825 surgical patients operated on in that year in