In this study, a total of 600 juvenile fish having 2.54 ± 0.07 g of average initial weight were used to investigate to the effects of different oil sources (fish oil, soybean oil, linseed oil and tallow) on the growth performance and body composition of Nile tilapia (Oreochromis niloticus, L.) during 14 weeks. Experimental diets were prepared as isonitrogenous (307.6 g kg-1 CP) and isocaloric (13.09 MJ DE kg-1 feed). At the end of the study, it was observed that there were no significant differences among the groups for average live weight, live weight gain, feed consumption, condition factor (CF), feed conversion ratio (FCR), protein efficiency ratio (PER), specific growth rate (SGR) and survival rate(P>0.05), but carcass composition (P<0.05). Consequently, it is concluded that there is no an important effect of different oil sources in fish feeds when they have sufficient essential fatty acids in their feeds.