This study was aimed to investigate the effects of pomegranate (Punica granatum) seed kernel meal (pskm) as a supplement in the diet of rainbow trout (Oncorhynchus mykiss), The experiment was carried out  in growth in a period of 90 days since the 12/11/2014 until the 12/03/2015 in Abzi Eksir Koesar complex , situated in south east of Tehran. 600 fingerlings with average weight of 6.74 gram and average length of 5.50 centimeter were divided to five treatments, The control group was without any pskm, and the other groups with added 1, 2, 3 and 4 percent pskm Respectively. For greater certainty each treatments had three replicates. Result indicated that pskm caused highest increased growth parameters in treatment 3 with 3 percent pskm, with other treatments and groups. growth parameters including weight with maximum of 47.74 gram , length were 15.03 centimeter ,weight gain with maximum of 41.15 gram, length increase with the maximum of 9.71 centimeter, Weight gain percentage with maximum amount of 572.1, specific growth rate with 0.45 and specific length rate with 0.1 mm. All growth parameters with the best value was seen in treatments 3.This result is due to the presence of high levels of appetite stimulants such as polyphenols of pskm (p<0.05). Result also indicated that the level of pskm in treatment 4, did not cause enough different with the control group, mainly because of higher amount of tannin in their diet.