Sea cucumber is presented as potential marine source of antimicrobial compounds. The purpose of this study is to evaluate antifungal effects of sea cucumber, Holothuria leucospilota, extracts on Aspergillus niger and Candida albicans. Methanol and chloroform extracts of the body wall, gonad and intestine of sea cucumber, H. leucospilota, collected from Persian Gulf, were evaluated for their antifungal activity against A.niger and C.albicans. The activity was determined using serial dilution method. Antifungal activity, minimum inhibitory concentration and minimum fungicidal concentration were evaluated by the different concentrations. Results showed that each of the extracts had antifungal effect at specified concentrations on the A.niger. All examined concentrations of Gonad methanol and intestine chloroform extracts had no inhibitory effect on C.albicans. Chloroform extracts of gonad and intestine had more fungicidal effect against A.Niger compared with C.albicans. Gonad chloroform extracts showed more fungicidal effect on the C.albicans at concentrations of 2.5, 5 and 10 mg/ml. Sea cucumber extract can be considered as an antifungal agent in various industries such as medicine and pharmaceutical industry.