Background and Aims: Cow's milk is a daily staple food for many individuals that can be contaminated with many toxins such as aflatoxin M1 (AFM1). AFM1 is a chemical form of the aflatoxin B1 produced by some species of Aspergillus genus like A. ochraceus, A. flavus, A. nomius, and A. parasiticus that can contaminate feed and forage cattle. This toxin enters into the milk after eating contaminated feed by cows. AFM1 can cause various dangerous diseases such as cancer and immune deficiency in humans. The present study is aimed to investigate the level of AFM1 in cow's milk in Jiroft, Kerman Province, Iran. Materials and Methods: A total of 90 cow’s milk samples were collected in spring and summer 2019 from available stores in Jiroft city. Enzyme-linked immunosorbent assay was used to measure AFM1 in all cow’s milk samples.Results: In the present study, AFM1 was found in 88 (97.8%) milk samples with a range of 0.2-90.62 ppt (mean, 20.07±24.46 ppt). AFM1 concentrations exceeded 50 ppt (maximum tolerance level of AFM1 in the European Union) was seen in 12 (13.3%) samples. Conclusions: The results of this study showed the presence of AFM1 in cow's milk in Jiroft city. So, in this region, many people are exposed to dangerous diseases such as cancer due to the consumption of milk contaminated with AFM1.