The incidence of pancreatitis after cardiopulmonary bypass is reported as < 0.1%. We report a milder form of pancreatitis characterized by hyperlipasemia and early intolerance to enteral nutrition without overt signs of clinical pancreatitis. A retrospective study was conducted in 72 patients who had received tube feeding. A statistically (p = 0.01) greater incidence of symptomatic hyperlipasemia was noted in post-cardiopulmonary bypass (PCPB) patients (42%, 5 of 12) than in non-PCPB patients (0%, 0 of 60). Four of the 5 PCPB patients who developed symptomatic hyperlipasemia received tube feeding into the stomach or duodenum before onset of their symptoms. The overall incidence of PCPB symptomatic hyperlipasemia during the study period was 1.3% (5 of 375). A prospective study was then carried out in 54 PCPB patients. Five patients became critically ill, and 4 of these developed symptomatic hyperlipasemia. Three of the 4 patients had received tube feeding into the stomach or duodenum before the onset of symptoms. In all cases, the symptoms of tube-feeding intolerance were mild and resolved with termination of feeding. This study suggests that critically ill cardiopulmonary bypass patients may be more susceptible to developing symptomatic hyperlipasemia, which is characterized by early intolerance to enteral nutritional support.