Mycotoxins are secondary metabolites produced by microfungi like Aspergillus, Penicillium, Fusarium, Alternaria. The enniatins are cyclic peptide mycotoxins and have produced by several strains of Fusarium sp. They have got biological activities like acting as enzyme inhibitors, antifungal and antibacterial agents. In this research the mutagenic effects of enniatin A1 and B1 were investigated with Ames assay. Ames is a test system which can detect mutations at celluler level. In this test Salmonella typhimurium TA98 and Salmonella typhimurium TA100, both in the presence and absence of S9 metabolic activation was used. Five different concentrations of Enniatin A1 and B1 (12.5 mu M, 25 mu M, 50 mu M, 100 mu M, 200 mu M) were exposed to these strains. In all test strains (Salmonella typhimurium TA98 and Salmonella typhimurium TA100) Enniatin A1 and B1 did not show mutagenic effect.