An analysis was accomplished to get information regarding presence of highly toxic and carcinogenic aflatoxin M1 (AFM1) in raw and processed samples of milk applying ELISA (enzyme linked immunosorbent assay). Investigation of a set of 100 samples (n=100) taken from different regional small-scale farms as well as grocery stores of Bangladesh containing three groups of milk including raw (n=50), pasteurized (n=25) and UHT (n=25), exhibited in total 53% AFM1 contamination where 70% contamination was found in raw milk ranging from 22.79-1489.28 ng/kg (mean value 699.07 ng/kg), 52% in pasteurized milk ranging from 18.11-672.18 ng/kg (mean value 99.77 ng/kg) and 20% in UHT milk ranging from 25.07-48.95 ng/kg (mean value 35.46 ng/kg). Among all the positive samples, 75% contaminated samples were above the European Communities prescribed limits (50 ng/kg) while having 25% samples still below this limit whereas 43% samples crossed the accepted limit of US regulations/Codex Alimentarius Commission regulations (500 ng/kg). Thus the findings of this study may lead to increase awareness regarding health impact of aflatoxin M1 and implementation of strict regulations by law enforcement bureaus of Bangladesh.