This study was conducted to evaluate dietary protein and carbohydrate requirement of juvenile Hawaiian limpets Cellana sandwincensis. A total of 64 juvenile limpets (3.12 ± 0.86 g) were fed five different dietary protein levels ranging from 270 to 470 g kg^-1 for 90 days. Carbohydrate and lipid levels were held constant at 180 and 49.7 g kg^-1, respectively. Weight gain and growth rates of the animals did not differ significantly (P>0.05) among the protein levels ranging from 270 g kg^-1 (0.30 % day^-1) to 470 g kg^-1 (0.23 % day^-1). Next, opihi were fed four diets with protein levels from 210 to 500 g kg-1 with a constant carbohydrate level at 120 g kg-1. Weight gain and specific growth rates of opihi increased with increasing dietary protein from 210 to 350 g kg^-1, and significantly (P-1. Elevated carbohydrate levels (180–370 g kg^-1) produced a significant difference (P-1 (0.27 % day^-1) and 320 g kg-1 (0.26 % day^-1). The weight gain of animals fed 180 and 370 g kg-1 carbohydrate diets were significantly (P-1. We conclude that about 350 g kg-1 protein and 320 g kg^-1 carbohydrate levels could be used for opihi.