This study was conducted in order to evaluate the efficiacy of a polyvinylpolypyrrolidone for protection against aflatoxicosis in broiler chicks. For this purpose 132 day-old broiler chicks (Hybro) were used. They were divided into four groups, each of 33 chicks. Group 1: control; Group 2: 3 g of polyvinylpolypyrrolidone (PVPP) per kg of diet; Group 3: 2.5 mg of aflotoxin (AF) per kg of diet; Group 4: 2.5 mg of AF per kg of diet plus 3 g of PVPP per kg of diet. The chicks were maintained on these treatments for 21 days, and then 15 broilers from each treatment group were killed for pathological examination. Hepatic lesions in broilers of AF treatment group were characterized as diffuse and severe hydropic degeneration, bile duct hyperplasia and periportal fibrosis. In the AF plus PVPP group, the liver of eight broilers showed slight or moderate hydropic degeneration. Grossly, the bursa of Fabricius was atrophied and sections revealed necrosis and depletion of lymphocytes from follicles in 12 broilers of the AF group and two of the AF plus PVPP group. In the spleen of six chicks from the AF treatment group Iymphoid areas were depleted. Thymuses from nine chicks fed the AF-alone diet showed atrophy and depletion of lymphocytes from the cortical and medullary areas. Similar changes were observed in the thymuses of four chicks from the AF plus PVPP group. The severity of atrophy in the lymphoid organs was more pronounced in the AF group than in the AF plus PVPP treatment group. In this study it was found that both the number of affected broilers and the severity of lesions were significantly decreased in the AF plus PVPP treatment group compared with AF-alone treatment. These findings suggested that PVPP can diminish the toxicity of aflatoxin in broiler chicks.