A 98 day feeding trial was carried out at the HATKO Anafartalar Fish Farm, Eceabat, (Çanakkale, Turkey), concerning the effect of dietary addition of soybean oil, sunflower oil, or fish oil on the growth of sea bass. Fish of initial mean weight 58.79 g, were housed within experimental net cages (25-50 fish/cage) and fed either a control commercial seabass ration, or the same ration supplemented with either 5 per cent fish oil (Experimental group III), 5 per cent soybean oil (Experimental group I), or 5 per cent sunflower oil (Experimental group II). At the end of the feeding trial, the live weight gain of experimental fish was found to be 79.53 g, 85.70 g, 86.31 g and 93.93 g for fish fed the control diet, soybean oil, sunflower oil or fish oil supplemented diet, respectively. Food conversion ratio was found to be highest level in experimental group II (2.25) and the lowest level within experimental group III (2.03). However, on the basis of analyses of variance, there were no significant differences between treatments on the basis of live weight gain and food conversion ratio. Carcass analysis showed no real differences among experimental groups by the end of the 98 - day rearing period, other than a slightly elevated carcass lipid content and decreased carcass moisture content of fish fed the sunflower oil supplemented diet. On the basis of these results the use of 5 per cent supplemental plant lipid over the use of fish oil had no adverse effect on the live weight gain, food conversion ratio, and viscerosomatic and hepatosomatic index fish. However, all experimental groups supplemented with dietary lipids had elevated carcass lipid levels compared with control fish fed the non - supplemented rations.