The effect of three individual strains of Laclobacillus (L. acidophilus NCC 12, L. acidophihrs NCC 36, L. acidophilus NCC 68) and two Bifidobacterium strains (B. bifrdum Bb13, B. bifidum NCC 381) on the growth and AFB(1) production of Aspergillus flavus NRRL 2999 was determined. The commercial MRS broth and skim milk medium were used to determine the effect of tested bacteria on the growth and AFBr production of A. flavus NRRL 2999. The bacteria were not effective in preventing the growth of A. flavus NRRL 2999 both in MRS broth and skim milk. However, higher levels of AFB(1) were obtained in the presence of individual strains of Lactobacillus and Bifidobacterium. The greatest difference was observed in the AFB(1) production of A. flavus NRRL 2999 in skim milk medium compared with MRS broth.