Mycotoxins are fungal metabolites which have been reported to have toxic, carcinogenic, mutagenic and teratogenic effects. Adverse effects of aflatoxin are recognized on human and animal health, many countries imposed standards for mycotoxin in food and feedstuff. The maximum allowable limit imposed by the European Union is 50 mg/L. 221 raw milk sampleswere collected from four dairy farms in Varamin region, Tehran province during fall 2011. The samples were placed in a refrigerator for 2 hours and then were centrifuged at 2000 g for 5 min. The fat layer was removed and M1 levels were measured using ELISA kits from Tecna Co. Italy. The mean± SD concentration of AFM1 in the studied samples was 21.4 ± 4.7 ng/L ranging from 0 to 405 ng/l. The results of the present study showed that the 26.7% of the studied samples were contaminated with AFM1 which is in accordance with the previous studies affirming the necessity of preventing measures to reduce mycotoxin contamination of feedstuff.