Dietary aflatoxin at concentrations of 1.25 microgram/g or above caused in broiler chickens a significant (P less than .05) decrease in the specific activities of pancreatic amylase, trypsin, lipase, RNase, and DNase. These enzymes are the primary enzymes of digestion for starches, protein, lipid, and nucleic acids. At concentrations of 2.5 microgram/g or above there was a compensatory pancreatomegaly that resulted in essentially normal total activity for trypsin, RNase, and DNase. Thus, aflatoxicosis was associated with reduced activity levels of enzymes that digest starch and lipid. This digestive deficiency could account for a malabsorption syndrome observed in field outbreaks of aflatoxicosis.