Abstract: This study was conducted to evaluate economic value of Sodium Bentonite (SB) originated from mines of Khorasan Province of Iran in broiler chickens diets. About 288 days old Ross strain broiler chickens were allocated to 6 experimental diets with 4 replications in a completely randomized design. Treatments were 0, 0.75, 1.5, 2.25, 3, 3.75% of sodium bentonite that used as top-dress. A basal diet was formulated according to NRC recommendations for starter (0-21 days) and grower (22-42 days) periods. The results showed that sodium bentonite had no significant effects on feed intake, feed conversion ratio, cost of 1 kg feed and cost of 1 kg meat production (p>0.05).