This study aimed to investigate the effect of high maize gluten protein diets on the white muscle free amino acid (FAA) concentrations of Atlantic salmon following feeding and to examine whether these tissue free amino acids profiles highlighted any dietary deficiencies in essential amino acids (EAA). Two isocaloric and isonitrogenous diets (52% protein, 20% oil) were formulated and mixed proportionately to give a total of five feeds in which maize gluten provided 0%, 16%, 32%, 48% and 64% of the total dietary protein (diets 0MG, 16MG, 32MG, 48MG, 64MG, respectively). Triplicate groups of 19 g Atlantic salmon were fed each of the experimental diets for a period of 40 days. At the end of the growth experiment, groups of four salmon from each diet were taken at 4, 8 and 12 h after feeding for the white muscle amino acids analysis. Although fish doubled their weights during the growth period, no significant differences were observed in specific growth rates, feed conversion ratios, protein digestibility and protein growth rates among fish fed the test diets. Total free amino acid (FAA) concentrations did not change at various times after a meal and this was also true for the majority of individual FAAs (except asparagine, which increased significantly 12 h after feeding). The most notable diet-induced changes in the white muscle were an overall reduction in essential FAA concentrations (threonine and lysine) as dietary maize gluten content increased and an increase in histidine and leucine. Correlations between dietary essential amino acids patterns and white muscle protein-bound amino acids were examined. The possibility of partial replacement of fish meal maize gluten up to 50% was demonstrated.