A prospective, randomized, multicenter study addressed the safety and efficacy of fluconazole therapy in 143 liver transplant patients. Seventy-six patients received daily oral fluconazole (100 mg), and 67 received nystatin (4 X 10(6) U) during the first 28 days after transplantation. Candida colonization occurred in 25% and 53% of patients in the fluconazole and nystatin groups, respectively (P = .04), and 13% and 34% of patients in the respective groups had Candida infections (P = .022). Of these patients, 10.5% in the fluconazole group and 25.3% in the nystatin group had superficial candidal infections (P = .024). Invasive candidiasis developed in 2 patients in the fluconazole group (2.6%) and 6 in the nystatin group (9.0%) (P = .12). There was no increased hepatotoxicity, cyclosporine interaction, or emergence of clinically relevant resistant Candida strains attributable to fluconazole. Thus, oral fluconazole (100 mg) is safe and reduces Candida colonization and infection after liver transplantation.