Abstract: This study was undertaken to investigate the growth performance and energy utilization of broiler chickens fed on conventional diets, based on soybean or canola, with fishmeal (SBM50 and Can50, respectively) or on Vegetable Protein (VP) diets without fishmeal (SBM75 and Can75). Feed intake was highest (p<0.001) on the SBM50 and Can50 diets and lowest on SBM75 diet. Birds in the SBM50 and Can50 diet groups were heavier (p<0.001) than the SBM75 and Can75 diet groups. Birds on SBM50 and Can50 diets achieved superior Feed Conversion Ratio (FCR), while birds on Can75 diet were the poorest. Mortality of birds was unaffected (p>0.05) between dietary groups. The Apparent Metabolizable Energy (AME) intake on the SBM50 and Can50 diets was higher (p<0.001) than in the VP. Fat intake was highest (p<0.001) on Can50 diet group while protein intake was unaffected by treatment. Heat Production (HP) was identical, but net energy of production (NEp) was improved (p<0.05) in the birds on SBM50 and Can50. Whole body energy as well as fat (p<0.05) and protein contents were also increased (p<0.01) in the SBM50 and Can50 dietary groups. Birds on SBM50 and Can50 diet groups retained higher energy as fat (REf) (p<0.05) and as protein (REp) (p<0.01). The efficiencies of utilization of ME for energy (kRE), protein (kREp) and fat (kREf) retentions were unaffected. The results demonstrated that birds on the conventional diets (SBM50; Can 50) utilized energy better and as such grew faster than the birds on VP (SBM75; Can75) diets.