Objectives: During recent years, increasing side effects for syntactic drugs have been motivated by more researchers for finding new compounds of the plant with antifungal activity. Dried fruits extract of Silybum marianum contain flavonoid compounds and until now, no studies have been conducted on the antifungal activates of methanolic extract of this plant. In this study, inhibitory potential of S. marianum methanolic extract on dermatophytes and saprophytes fungi was investigated in vitro compare to clotrimazol.Method: Antifungal activities of S. marianum seeds extract were evaluated against pathogens (Trichophyton mentagrophytes, Epidermaphyton folocosom, Microsporum canis) and saprophytes (Aspergillus niger, Candida albicans) fungi with different methods such as, disc diffusion (60, 30, 15, 7.5, 3.2 and 1.6 mg extract per disc), pour plate and broth (50, 25, 12.5, 6.2, 3.1, 1.5 mg ml-1 extract in medium). Concentration of cloterimazol as a control was 10 µg ml-1.Results: Our results showed that, S. marianum seeds extract prevents the growth of dermatophytes more than saprophytes fungi. The best inhibitory effects of extract (6.2 mg ml-1) in Microsporum canis and Epidermaphyton folocosom cultures were achieved by porplate and broth methods that were similar to our results with 10 mg ml-1 cloterimazol. No inhibitory effects were observed in Aspergillus niger and Candida albicans cultures.Conclusion: With attention to our finding, components of the Silybum marianum extract have antifungal effects on the growth of dermatophytes.