The present study examined the effects of dietary supplementation with nucleotide (inosine monophosphate product, IMP) on the growth performance, feed utilization, and non-specific immune responses of juvenile tilapia Oreochromis niloticus. Triplicate groups of tilapia (initial body weight, $7.4{pm}0.04$ g) were fed experimental diets containing 0%, 0.05%, 0.1%, and 0.2% IMP. Fish were fed six times a day until apparent satiation for 13 weeks. At the end of the feeding trial, final body weight and food utilization of fish fed 0.1% IMP were significantly higher than those of fish fed the control diet. Results of hematological parameters were not affected by dietary IMP. However, blood protein level was significantly higher in the 0.05% treatment, as compared to that of the control and 0.2% IMP diets. Myeloperoxidase activity was higher in fish fed 0.1% IMP than in fish fed the control and 0.2% IMP diets. These results suggest that dietary supplementation with IMP can enhance the growth performance, feed utilization, and innate immune response of juvenile tilapia. The optimal IMP supplementation level appears to be 0.1% in practical feed formulations for tilapia.