A 60-day feeding trial was carried out to evaluate the effect of dried periphyton supplementation on growth performance, feed utilization and proximate analysis of chemical composition in Nile tilapia, Oreochromis niloticus. Five diets (isonitrogenous and isocaloric) containing five levels of dried periphyton 0 g (diet 1, control), 2.5 g (diet 2), 5 g (diet 3), 7.5 g (diet 4) and 10 g (diet 5) kg^-1 diet were formulated. At the end of trial, the highest wight gain, specific growth rate, survival rate and protein efficiency ratio were recorded by fish fed diet 4 and diet 5 which supplemented with 7.5 and 10 g dried periphyton kg^-1. No significant differences (P > 0.05) were found in all chemical composition; dry matter, crude protein, crude lipid and ash content of tilapia fed different level of dried periphyton.  The obtained results suggested that the best level of dietary dried periphyton in Nile tilapia feed was 7.5g or 10 g kg^-1 diet as a feed additive to promote growth.