Abstract: This study was conducted to determine performance and biochemical and histopathological changes in Chicks that Clinoptilolite (CLI) was added to diets containing Aflatoxins (AF) from 1-42 days of age. A total of 480, One-day-old broiler chicks (Ross 308) was divided into 6 treatments: control; basal diet prepared with uncontaminated diet, control containing AF (0.5 mg kg ¹), control containing AF (1 mg kg ¹), control containing CLI (20 g kg ¹), control containing AF (0.5 mg kg ¹) + CLI (20 g kg ¹) and control containing AF (1 mg kg ¹) + CLI (20 g kg ¹) ) each consisting of 80 chicks. Chickens were monitored daily and then body weight and feed consumption were recorded. Plasma enzymatic and non-enzymatic parameters showed progressive changes in birds examined 21 or 42 days after dietary aflatoxin treatments. Compared to controls, the AF treatment significantly (p<0.05) decreased body weight gain, feed intake, serum total protein, albumin, cholesterol, uric acid, calcium, phosphorus, alkaline phosphatase (ALP) and from enzymatic parameters Lactate Dehydrogenase (LDH) and aspartate amino transferase (AST) increased. Decreases in serum parameters caused by AF was significantly (p<0.05) ameliorated by CLI. A similar increase was obtained in feed intake and body weight gain by adding CLI to the AF-containing diet (p<0.05). Histopathologic examination revealed severe fatty change, regeneration foci of liver cells, fibrosis of portal regions and bile ductule hyperplasia. The addition of CLI to the AF-containing diet decreased the severity of lesions (hepatic lipidosis, regeneration foci and bile-duct hyperplasia) in the livers. Prolonged exposure to low concentration of the toxin produce severe changes in fat metabolism and bile ductule proliferation. These results suggest that CLI (20 g kg ¹) was effective for the protection of AF-toxication in broiler chicks and addition of CLI effectively diminished the detrimental effects of AF on traits investigated.