The goal of this study was to investigate the in vitro effect of omeprazole on Candida albicans and analyze the antifungal activity of omeprazole. A total of 150 samples were collected from the patients in Bakirköy Dr. Sadi Konuk Education and Research Hospital and samples were evaluated for C. albicans. After the microbiological analyses, fifty one patients (18 men and 33 women) between 0 and 78 of age were found to be C. albicans positive and they were included in the study. All consecutive isolates of C. albicans were recovered from blood, urine, sputum, oral cavity, vagina, catheter tip and ascitic fluid. Antifungal suspectibility test was carried out by microdilution assay according to the method outlined in the NCCLS document M27-A. It was determined that omeprazole is fairly effective in particular MIC range. Furthermore, it was observed that omeprazole in high concentrations support the growth of fungi.