Technical Abstract: Current trends in trout production include decreasing levels of fishmeal content in feeds for faster growing strains of fish; therefore, taurine may be a limiting nutrient in support of elevated growth for strains of genetically-improved rainbow trout. A 12-week feeding trial was conducted using a factorial treatment design with taurine supplementation (3 levels) and methionine supplementation (3 levels) as the main effects. The diets were formulated to contain only plant proteins. All diets were formulated to contain 43.8% crude protein from intact protein and 20% lipid. The unsupplemented plant diet had taurine levels below the detection limit of 0.1g/kg diet and 14.9g/kg total sulfur amino acids (met+cys). Taurine supplementation improved growth (p=0.096, g gain per fish) and taurine supplementation at a level of 5 g/kg diet increased feed consumption (p=0.095), but did not alter protein retention efficiency, energy retention efficiency or feed conversion ratios. Methionine supplementation reduced growth (p=0.010, g gain per fish) and feed consumption (p=0.055) but did not alter protein retention efficiency, energy retention efficiency or feed conversion ratio. Reduced intraperitoneal fat deposition was seen with dietary methionine supplementation, whereas taurine supplementation had no such effect. Dietary supplementation with methionine or taurine had no effect on plasma GH levels, whereas methionine supplementation (5g/kg diet) was associated with decreased plasma IGF-I concentrations