The feeding stimulative effects of nucleotides and their related compounds on juvenile cobia (Rachycentron canadum) were investigated. Among these nucleotides only inosine-5’-monophosphate (IMP), guanosine-5’-monophosphate (GMP), uridine-5’-monophosphate (UMP), and adenosine-5’-diphosphate (ADP) showed high feeding stimulative responses. In contrast, nucleosides, nitrogen bases, and ribose were not effective. The optimal concentrations of IMP, GMP, UMP, and ADP for juvenile cobia were 2.9, 8.1, 2.8, and 6.6 mmol/kg dry pellets, respectively. These effects of the nucleotides were synergistic when supplemented in pairs. The synergic effects disappeared when the 4 nucleotides were supplemented together.