Abstract: This experiment was conducted to investigate the effects of an organic acids and etheric oils mixture (BIACID™) on fattening performance, carcass quality and some blood parameters of broilers. Therefore, a total of 160 days-old Ross 308 broiler chicks were assigned to 2 groups with 4 replicates each containing 20 chicks. The groups were employed: Control group (C) without additive, Group (A), which supplemented with 1 kg ton-1 organic acid mixture containing etheric oils. Experimental period lasted 42 days. There was no statistical difference in the cases of live weight, live weight gain, feed consumption, feed conversion ratio, hot and cold carcass yield, liver, gizzerd, heart, abdominal fat pad weight and their ratios to hot carcass weight, the mean intestinal content pH and total intestinal weight scores, serum total protein, triglyceride and cholesterol levels of groups C and A. Only the jejenum length scores were statistically longer of group A than group C. As a result, the values obtained by the addition of organic acid mixtures containing etheric oils to broiler ratios are generally in an acceptable level.