This study was initiated to determine whether a specific fatty acid marker from hepatic lipids could be identified to confirm aflatoxin exposure in chickens. Male broiler chicks (240) were reared to 21 days of age on diets containing 0, 625, 1.25, 5.0, and 10.0 ppm aflatoxin. Live weights and organ weights differed significantly among the dietary groups. Total liver lipids increased significantly (P less than .001) with increasing aflatoxin levels. Separation of extracted lipids into neutral and polar fractions established that this increase in hepatic lipid was accounted for almost entirely by increases in neutral lipid fractions. A gain of 117% occurred in the weight of neutral lipids as aflatoxin increased from 0 to 10 ppm. In both neutral and polar lipid fractions subsequent chromatographic analysis of fatty acid methyl esters (FAME) showed linear increases in the monoenoic fatty acids with increasing aflatoxin. No single FAME from either lipid fraction was suitable for confirming aflatoxin exposure.