In the process of understanding impact of aflatoxicosis, it revealed that a dietary concentration of 300 ppb aflatoxin B1 impaired the performance in terms of body weight gain, feed intake, and utilization efficiency of feed, energy and protein, and also suppressed both cell mediated and humoral immunity in broiler chickens during 0-6 weeks of age. Aflatoxicosis resulted in atrophy of bursa of Fabricius, hypertrophy of liver and histopathological changes in liver characterized by marked destruction of hepatic cords, dilatation and congestion of central veins, mild adenomatous necrotic foci and mild to moderate deposition of fats in the hepatic parenchyma.