This study was conducted in the laboratory of fungi of the Department of biology of the collage of Science in Mustansiriyah University to investigate the contamination of grain (maize ) displayed in the markets of the city of Baghdad mycotoxins type aflatoxin, was isolated the fungi associated with contamination of maize and the number of 10 isolates where the record Aspergillus flavus isolates the most isolates occur 7 Aspergillus niger isolates followed by 2 isolates and one isolated Penicillium sp. ، Aspergillus flavus isolates done Pathogenicity test to identify the isolates of the study. Four isolates were identified (Afla1, Afla2, Afla3, Afla4). The results of the aflatoxin detection in four different samples of positive yellow maize samples showed that all samples tested were contaminated with Aflatoxin, sampled from different regions, Adhamiya, Al-shaab and Palestine Street, had the highest pollution rate of 2149μg/g for Afla 1, while Afla 2 recorded the lowest pollution rate of 114μg/g.