Supplementation of nucleotides into fish diets can be an alternative method to manage disease problems in aquaculture, since it was reported could improve the growth rate and immunity of some aquaculture species. The present study assessed the growth and immune performance of Asian seabass (Lates calcarifer Bloch 1790) after being fed diets containing different levels of a commercial nucleotide (Optimun®) and a purified mixture of nucleotides containing AMP (Adenosine monophosphate), IMP (Inosine monophosphate), UMP (Uridine monophosphate), GMP (Guanidine monophosphate) and CMP (Cytidine monophosphate) in equal amounts. Six nucleotide supplemented diets and a control diet were used in this study, namely O1 (Optimun® 0.25 %), O2 (Optimun® 0.5 %), O3 (Optimun® 0.75 %), P1 (0.25 % mixed pure nucleotides), P2 (0.5 % mixed pure nucleotides), P3 (0.75 % mixed pure nucleotide) and C (control/diet without nucleotide supplementation). The treatment diets were fed to juvenile Asian seabass (average initial weight of 13.19 g ± 0.58 g) at 3 % body weight per day for six weeks. The results showed that weight gain, total serum protein and globulin were significantly higher in fish fed diet P2 (0.5 % of a mix pure nucleotides) compared to the control group (P 0.05). In conclusion, supplementation of nucleotides in Asian seabass diet may have positive effect on growth performance and immune response of the fish, while diet containing 0.5% of mixed pure nucleotides tend to have a better result compared to other diet groups.