Raw milk samples (n=28) obtained from milk tanks in 3 dairy plants of different regions and commercial milks (n=100) were collected from six cities. These samples were analyzed for the level of aflatoxin M_1 contamination using immunoaffinity columns and high performance liquid chromatography coupled with fluorescent detectors. Confirmation of aflatoxin M_1 (AFM_1) identified in positive samples was based on the formation of the hemiacetal derivative (AFM_2a) after derivatization with trifluroacetic acid. The average concentrations of aflatoxin M_1 in the raw milks were 25.1 ng/kg, and those values in commercial milks were 29.8 ng/kg. The highest level of aflatoxin M_1 in milk was 72.7 ng/kg. These results showed that the contamination of aflatoxin M_1 in milks consumed in the Korea was quite low compared to the standard in Korea Food Code (aflatoxin M_1 500 ng/kg).