This study was carried out to determine the effect of earthworm meal usage on growth performance and body composition in fry rainbow trout feed. The 360 fish with an average weight of 5.05 +/- 03.61 g were used in the study. In the experiment, four different feeding groups were designed with 3 replications. These groups are SUO (Control), SUI, SU2 and SU3 groups which contain 0, 10, 20 and 30% earthworm meal (SU), respectively. Fish were fed three times a day for 90 days with these experimental feeds which were prepared to be 2.5% of the fish live weight. At the end of the study, SU3 group reached the highest weight gain with 259.40%, followed by SU2, SU1 and SU0 (211.17%, 182.76%, 113.68%, respectively). The difference between the SU3 group and the other groups was statistically significant in terms of live weight gain, specific growth rate, feed conversion ratio and protein efficiency ratio (P < 0.05). Hepatosomatic index was statistically significant between all groups (P < 0.05). As a result, considering the growth performance measurement criteria, it was determined that the use of 20-30% earthworm meal in the rations of fry rainbow trout could increase fish growth significantly.