Five feeding experiments were conducted with 414 commercial broiler chicks (Anak strain) to investigate the effects of cooked castor oil bean meal diets supplemented with DL-methionine and L-lysine on growth performance, blood indices, internal organs and mortality of broiler birds.Results showed that increasing levels of cooked CBM in the diets decreased (P>0.05) average daily feed intake (ADFI), average daily weight gain (ADG), efficiency of feed and protein utilization, and decreased (P>0.05) packed cell volume (PCV), haemoglobin concentration (Hb) and apparent retention of dry matter, nitrogen, ether extract and nitrogen-free extract. Birds fed 0, 10 and 15% CBM diets had similar growth rate, PCV and Hb. Birds fed the 20% CBM diet had relatively lower (P>0.05) growth rate than birds fed the 0, 10 and 15% CBM diets. Supplementation of the diets with DL-methionine or with L-lysine enhanced (P>0.05)birds' performance, PCV, Hb and apparent retention of nutrients at the 10, 15 and 20% CBM inclusion levels. No lesions were observed in all the internal organs examined.The results showed that dehulled and detoxified castor oil bean meal is a potential protein-rich feed ingredient.