experiment was carried out to investigate the effect of dietary humic acid supplementation on performance of broiler chicks. One hundred  and eighty Arbor Acers broiler chicks were assigned equally into five treatment groups. Humic acid was supplemented to basal diet 0 (control), 1.00, 2.00, 3.00 and 4.00 g/kg respectively. Chicks fed diet with different levels of humic acid had significantly (P<0.05) greater production performance than the control group. Humic acid had significantly improved the digestibility of crude protein and either extract. Feeding diet with humic acid significantly decreased  plasma content of cholesterol, malondialdehyde (MDA) and low-density lipoprotein (LDL) while increased glucose, total protein, triiodothyronine, thyroxine, glutathione, globulin, -γ globulin, compared to control group. Humic acid significantly increased the percentage of dressing and decreased abdominal fat compared to control. In conclusion, humic acid supplementation at 1.00, 2.00 and 3.00 and 4.00 g/kg diet was superior regarding growth, digestibility, and economical return, without negative effects on blood and carcass traits of broilers.