Aflatoxins are a group of highly toxic secondary metabolic products of some Aspergillus spp. Aflatoxin M1 (AFM1) is the hydroxylated metabolite of aflatoxin B1 and may be found in milk and dairy products such as cheese. This study was conducted to determine the AFM1 levels in Turkish white, kashar and tulum cheeses. For this purpose, 80 cheese samples were randomly obtained from markets and bazaars in Istanbul and analyzed for AFM1 by ELISA. While 39 of 80 cheese samples (48.7%) were negative for AFM1, 18 white cheese, 12 kashar cheese and 11 tulum cheese samples, in total 41 samples (51.3%) were found to be contaminated with AFM1 in the range of 0.052-2.52 mu g/kg. The mean AFM1 values of examined white, kashar and tulum cheese samples were detected as 0.42, 0.25 and 0.38 mu g/kg, respectively.