The extent of physiological disturbance in a preoperative population of 100 elderly patients scheduled for elective major surgery was measured. Haemodynamic, respiratory and renal function were evaluated preoperatively in the intensive care unit. Of these patients 13% had serious problems requiring either postponement of the operation (7%) or its cancellation (6%). Cardiac index was 2.2 l/min/m2 or less in 11% of patients; creatinine clearance 50 ml/min or less in 19% of patients; mean blood pressure was equal to or exceeded 120 mmHg in 15% of patients and intrapulmonary shunt equalled or exceeded 15% in 10% of patients. The mean duration of stay in the intensive care unit was four days, including the preoperative day. The logistics of preoperative admission were implemented without undue difficulty.