The causes of appearance of mold in the silage, genus and species of fungi which biosynthesize mycotoxins, acting consequences of micotoxins, prevention of fungi growth and possibilities to prevent their negative effects are shown in this paper. Also, the results of mycotoxins presence in the silage (corn and lucerne) in Vojvodina in the period 2000-2004 are presented. The most commonly found mycotoxins were zearale-none in 60.6% of analyzed samples and DAS in 30.3% of samples. Silage contamination with ochratoxin A, aflatoxin B1 and T-2 toxin was between 15.2 and 21.2%. The content of mycotoxins DAS and T2 toxin was above the values allowed by regulative. The solutions which contribute to the prevention of development of the molds and elimination of negative effects of mycotoxins in silage were analyzed and suggested