An experiment was conducted at the fish experimental station of the Al-Azhar university, Faculty of Agriculture to study the effect of dietary plant protein level (25% and 30 %) and stocking density (50 and 100 fish/m3) on performance of Nile tilapia (Oreochromis niloticus) during the period from 1.5. 2000 to 31.10.2000. Four circular fiberglass tanks each of one cubic meter of volume used representing four treatments two protein levels and two stocking densities. Results obtained can be summarized as follows: - Regardless of stocking density increasing the protein level fed from 25% to 30% increased significantly (P