Spread of diseases is one of the most important problem in aquacultural system. Hence, growth rate and immune system should be stimulated by addition of chemical products such as enzymes, antibiotics and natural extract compounds to diet. Due to undesirable side effects of chemical products and antibiotics to aquatic animals, farmers prefer to use natural additives that not only stimulate the immune system but also promote growth. In this study, effects of alcoholic extract of pomegranate Punica granatum peel on some hematological and biochemical parameters, including RBC, Hb, Hct, MCV, MCH, MCHC, WBC, TP, CHO, GLU, LDL, HDL, Glb, TG, GOT, GPT, Alb, ALK, LDH, lysozyme activity as well as body chemical composition (protein, moisture, ash and oil contents) and growth parameters (SGR, CF, WGP, FCR and PER) of common carp fingerlings were studied. To do this, 165 fish with an average weight; 11.73 ± 1.81g were divided randomly into five groups with three replicates. Fish were fed with diets containing different concentrations of ethanol extract of pomegranate peel (Zero: (as a control), 50, 150, 300 and 600 mg/kg of diet) for 75 days. At the end of experiment, all fish were sedated for morphometric measurement and blood sampling. Results showed no significant difference in body chemical composition of fish between pomegranate peel treatments and the control. Specific growth rate of fish in groups 300 and 600 mg/kg of diet, body weight percentage gain in group 300 mg/kg of diet and the average final weight in all groups treated with pomegranate peel extract in comparison with the control group showed significant improvement (P 0.05). The present study showed significant increases in Hb, Hct and RBC in groups 300 and 600 mg/kg of diet and the highest values were observed ??in group 600 mg/kg of diet (P 0.05) whereas other hematological parameters such as MCV, MCH, MCHC, WBC and lymphocytes (Lym), monocytes (Mon) and neutrophils (Neu) were not significantly different from the control group. Among serum biochemical parameters, total protein in groups 150, 300 and 600 mg/kg of diet showed a significant difference with other groups (P 0.05).The highest amount of total protein was observed in treatment 150 mg/kg of diet. Lysozyme activity was significantly enhanced in all diet containing pomegranate peel extract/kg of diet in comparison with untreated control group (P 0.05). In conclusion, the present study revealed an overall improvement in growth and hematological parameters and lysozyme activity when 300 and 600 mg pomegranate peel extract were used in the diet. However, biochemical parameters were not affected by pomegranate peel extract additives, except for total protein. Based on the present study the levels of 300 and 600 mg pomegranate peel extract per kg of diet can be recommended for improvement of growth parameters and immune system for common carp fingerlings. Keywords: pomegranate peel extract, Punica granatum , growth, body chemical composition, hematological parameters, biochemical parameters, serum lysozyme activity, common carp, Cyprinus carpio