A study was conducted to determine the effect of dietary protein level on growth performance, body composition and haematological parameters in juvenile starry flounder. Only fish meal was used as protein source to formulate five isoenergetic experimental diets at various protein levels were fed to triplicate groups of starry flounder (mean initial body weight: in a recirculating rearing system for 54 d. (1) Weight gain rate (WGR) and specific growth rate (SGR) were significantly improved with increasing dietary protein from 34.85% to 51.54% (<0.05) and leveled off.protein efficiency ratio (PER) of fish fed diet with 51.54% protein level was significantly higher than those of the other groups (<0.05). Protein retention efficiency (PRE) at 51.54% dietary protein was also significantly higher than those of the groups with 34.85%, 46.54% and 56.69% dietary proteins (<0.05), but there were no significant difference with 40.48% dietary protein (>0.05). analysis based on weight gain rate (WGR) indicated that dietary protein requirement for juvenile starry flounder was 53.65%. (2) Proximate composition of fish body was significantly affected by dietary lipid level. Body protein content significant difference <0.05) to 34.85% dietary protein group, while there were no significant differences with 40.48%, 46.54% and 56.69% groups (>0.05).Fat content in whole body decreased with the increase in dietary protein level. showed a reverse trend compared to Body ash content was not significantly affected by dietary protein level. (3) Plasma total protein (TP) concentration increased with increasing dietary protein level up to 51.54%, and then leveled off. Plasma urea nitrogen (UN) content at 51.54% dietary protein was significantly lower than those of 34.85% and 46.54% dietary proteins (<0.05), while there was no significant difference with 40.48% and 56.69% dietary proteins (>0.05). In considering these results, it was concluded that the optimum dietary protein requirement for