Nowadays the herbal drugs products and their derivates are used as an immunostimulants, growth promoters and physiological booster in aquatic animals. In this research, the effect of persimmon leaf extract (Diospyros kaki) on the hematological and immunity indices of juvenile’s common carp have been investigated. For this purpose, a total of 400 juvenile common carp with an average weight of16.11±2.75 were randomly divided into four groups with three replicates. Persimmon leaf extract in values of 0, 1, 3 and 5% were added into diets and fish were fed with 3% of body weight for 60 days at 3 times. Comparison of the blood parameters indicated that the highest levels of hemoglobin, hematocrit and red blood cell were observed in the treatment containing the high concentration of persimmon leaf extract (P<0.05). The differential count of white cells indicated that highest concentrations of monocytes, lymphocytes and neutrophils were found in the treatment containing 5% of leaf extract. There was no significant difference between total protein and glucose in experimental and control treatments (P>0.05). The level of cholesterol was significantly higher in 5% treatment (P<0.05). The activity of protease and alkaline phosphatase enzymes, as well as the levels of immunoglobulin and lysozyme in mucus of fish, were significantly higher in treatments than in control and the highest amount was observed in 5% treatment (P<0.05). Based on the results, it can be concluded that the leaf extract can be used as a nutritional supplement to strengthen safety indicators in common carp.