Three feeding trials were conducted to evaluate the effects of feeding rate and water temperature on growth and body composition of juvenile Korean rockfish, Sebastes schlegeli rearing at 3 different water temperatures. A total of 270 fish (each experiment) individual body weight (BW) averaging $16{pm}0.3g$ ($mean{pm}SD$) were fed a commercial diet for 4 wk at $16^{circ}C$, $20^{circ}C$, and $24^{circ}C$. At each temperature, triplicate tanks were assigned to one of 6 feeding rates: 1.5%, 2.5%, 2.8%, 3.1%, 3.4%, and satiation (3.7% BW/d) at $16^{circ}C$, 1.9%, 2.9%, 3.2%, 3.5%, 3.8% and satiation (4.1% BW/d) at $20^{circ}C$ and 1.7%, 2.7%, 3.0%, 3.3%, 3.6%, and satiation (3.9% BW/d) at $24^{circ}C$ water temperature. Weight gains of fish in satiation and 3.4% groups at $16^{circ}C$, in satiation and 3.8% groups at $20^{circ}C$ and in satiation and 3.6% groups at $24^{circ}C$ were significantly higher than those of fish in the other treatments (p<0.05). A broken line regression analysis of weight gain indicated that optimum feeding rates of juvenile Korean rockfish were 3.41% at $16^{circ}C$, 3.75% at $20^{circ}C$ and 3.34% at $24^{circ}C$ water temperature. Results of the present study indicate that the optimum feeding rate could be >3.1% but <3.41% at $16^{circ}C$, >3.5% but <3.75% at $20^{circ}C$ and >3.0% but <3.34% at $24^{circ}C$. As we expected results suggest that fish performed better at $20^{circ}C$ than $16^{circ}C$ or $24^{circ}C$ water temperature and the optimum feeding rate could be 3.1% BW/d to 3.7% BW/d in 16 g of juvenile Korean rockfish.