Three experiments were conducted to determine limiting amino acid of wheat-canola meal diet for broiler starter chickens. Different levels of synthetic amino acids (arginine, methionine, lysine and glutamic acid) were supplemented to diets composed of wheat, 30% of canola meal (RSM), animal fat and other minor ingredients. Chickens fed experimental diets were kept for 4 weeks and data of weight gain, feed efficiency, mortality, perosis, kidney arginase activity, and level of urea, uric acid and free amino acid in plasma were. obtained. Weight gain of chickens fed RSM diets were significantly (P $lt; .05) improved by supplementary lysine (.24%). Supplementary arginine, methionine, glutamic acid or combinations of these amino acids did not improve weight gain. Feed efficiency was significantly improved by supplementary glutamic acid. Mortality and perosis score were not significantly influenced by treatments. Data of kidney arginase activity, plasma urea and plasma free amino acid supported the weight gain data which showed that limiting amino acid is not arginine or methionine but lysine. Level of plasma uric acid was not significantly influenced by amino acid supplementation to RSM diets.