Sixty-two cases of peritonitis due to peptic ulcer perforation were diagnosed between January 2000 and December 2000. Of these 62 cases, 23 isolates of Candida in 23 cases (CP) were cultured from peritoneal fluid. Cultures of peritoneal fluid of 10 (BP) of the remaining 39 cases was positive for bacteria only. Cultures of peritoneal fluid of the remaining 29 cases was negative. Comparison of CP, BP and culture-negative cases did not reveal any significant risk factor. Of the 23 Candida isolates, the Candida species and 48-h MICs of fluconazole and amphotericin B (mean, range ug/ml) were C. albicans 18 (0.688, 0.125-1.0; 0.297, 0.031-0.5), C. glabrata 3 (0.542, 0.125-1.0; 0.25, 0.125-0.5), C. tropicalis 1 (0.25; 0.5), C. intermedia 1 (1.0; 0.125) respectively. Mortality rates of CP, BP and culture-negative peritonitis due to infection were 5/23(21.7%), 0/10 and 1/29(3.4%) respectively. Without effective antifungal therapy, the mortality rate of CP was not low.