In a series of 102 patients with cancer of the oesophagus or gastric cardia in whom surgery had been performed, postoperative respiratory infection, respiratory failure and mortality secondary to respiratory complication occurred in 55.8, 34.3 and 21.6 per cent respectively. The incidence of complications correlated well with the pre-operative peak expiratory flow rate when it was less than 65 per cent of the predicted normal value. However, the predictive ability of peak expiratory flow rate was much less than the patient's age, pre-operative serum albumin level, pre-operative Pa,O2 and number of surgical wounds when all risk factors were considered. Significantly more complications occurred when the patient was greater than 65 years old, Pa,O2 was less than 10 kPa, serum albumin was less than 39 g/l and when the operation required three incisions. These findings may serve as guidelines for identification of high-risk patients in the future.