Over a 2-year period, all surgical patients from whom Candida was isolated from intra-abdominal specimens were evaluated. All but 1 of the 49 evaluable patients had either a spontaneous perforation (57%) or a surgical opening of the gastrointestinal tract (41%). Candida caused infection in 19 patients (39%), of whom 7 had an intra-abdominal abscess and 12 peritonitis. In the other 30 patients (61%), there were no signs of infection and specific surgical or medical treatment was not required. Candida was more likely to cause infection when isolated in patients having surgery for acute pancreatitis than in those with either gastrointestinal perforations or other surgical conditions. The development of a clinical infection was significantly associated with a high initial or increasing amount of Candida in the semiquantitative culture. Surgery alone failed in 16 of 19 patients (84%), of whom 7 died and 9 recovered after combined antifungal and surgical treatment. The overall mortality and the mortality related to infections were significantly higher in the patients with intraabdominal candidal infections than in those without such infections.