The purpose of this study was to determine the levels of aflatoxin M1 (AFM1) in the milk of cows in the villages of Kayseri province, Turkey. Ninety milk samples were investigated for AFM1 contamination using the enzyme linked immunoassay (ELISA). The mean value of AFM1 levels was 59.9 ng/L, 95% confidence interval was 54.4-65.5 ng/L, and standard deviation was 26.6 ng/L. For 63 samples (70%) the values were significantly above the limit permitted by European Union criteria (EU) and the Turkish Food Codex (TFC) (P < 0.05). However, the differences in AFM1 levels between villages were not significant (P > 0.05). In conclusion, since the level of AFM1 in the milk of cows was higher in Kayseri province, this must be seen as a significant public health problem. Further research must be conducted on the levels of AFM1 in milk samples sterilized using ultra high temperature (UHT).