Intraabdominal complications (IAC) after cardiopulmonary bypass often are difficult to diagnose and are associated with high mortality (13% to 67%). From 1984 to 1991 we retrospectively analyzed 53 patients undergoing cardiopulmonary bypass for coronary artery bypass grafting, valve reconstruction, or arch reconstruction who experienced 55 episodes of IAC and compared them with matched control patients (matched for operation, age, and sex). The overall incidence of IAC was 0.65%. Univariate analysis identified the following preoperative variables as significantly (p < 0.05) increasing the risk of IAC: history of congestive heart failure, chronic renal failure, and more than three medical problems. A history of congestive heart failure was the most powerful predictor by multivariate analysis (p = 0.045). Early post-cardiopulmonary bypass complications were increased significantly in IAC patients. These included acute renal failure (p < 0.0001), cerebrovascular accidents (p < 0.03), and lower extremity ischemia (p < 0.05). Twenty-eight of 38 laparotomies performed were diagnostic. However, analysis of 58 combined clinical, radiologic, and laboratory tests failed to identify which predicted the diagnostic utility of a laparotomy. Fifteen of the 53 IAC patients (28%) survived: 8 patients had had a therapeutic laparotomy, 1 patient underwent a nondiagnostic laparotomy, and 6 patients were managed nonoperatively. Multivariate analysis identified ventilator dependence (p = 0.004) and acute renal failure with creatinine level greater than 1.9 mg/dL (p = 0.011) as the most powerful predictors of mortality regardless of intervention. These data suggest a profile of cardiac surgical patients at risk for IAC as well as those patients who are most likely to benefit from timely intervention.