The study was conducted to investigate the effect of dietary supplementation with turmeric powder as a natural growth promoter on performance, carcass traits, humoral immune responses and serum biochemical parameters in male broiler chickens. A total of 300 one-day-old male broiler chicks (Ross 308) were allocated to four treatments with five replicates. The dietary treatments consisted of the basal diet as control, 3.3, 6.6 and 10 g/kg turmeric powder added to the basal diet. The curcumin content of the turmeric powder was 1.16±0.03% by weight. Body weight gain and daily feed intake of chickens at different periods were not influenced by the dietary treatments. Broilers fed turmeric supplemented diets exhibited better feed efficiency over the grower and entire experimental periods in comparison with control group (P