PURIFIED diets in which a crystalline amino acid mixture serves as the sole source of amino nitrogen have been developed for a number of species. Among the successful mixtures which have recently been developed are ones capable of supporting near-normal growth of young chickens (Adkins et al., 1961a; Klain et al., 1960), egg production of hens (Fisher and Johnson, 1956; Adkins et al., 1961b) and nitrogen balance in the adult male chicken (Leveille and Fisher, 1958). However, except for a study by Vohra and Kratzer (1959), little attempt has been made to develop a free amino acid diet for the turkey poult.The desirability of developing a free amino acid diet for studying amino acid requirements and interrelationships in the turkey is obvious. The following studies were thus initiated to develop a crystalline amino acid mixture which, when added to a purified poult diet as the sole source of amino …