The presence of fumonisin has not been regulated in the legislation of the Republic of Serbia. Therefore, the data on contamination of cereals, especially corn, which is highly susceptible to contamination by this toxin, are not sufficient. This paper presents the results of testing the corn samples collected in the autumn 2009 on the territory of Bačka. Samples were analyzed for the contents of fumonisins and it was determined whether there is a correlation between the moisture content, total number and class of fungi, as well as the content of aflatoxin, ochratoxin and zearalenone. Using enzymatic immunoaffinity method it was discovered that the highest percentage of samples were contaminated with fumonisins, which was probably due to the presence of Fusarium molds as the most abundant ones. The positive samples contained fumonisin in the concentrations from 0.030 to 1.52 mg kg−1. The influence of the climate and moisture content of grain on fungal contamination and mycotoxin production was analyzed in order to investigate the predictability of the presence of mycotoxins.