Grouped or individual amino acids from two diets were deleted to evaluate the effects of amino acids on larvae and adults of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Larvae died when fed with diets free of 10 exogenous essential amino acids (arginine, isoleucine, leucine, lysine, histidine, methionine, phenylalanine, threonine, tryptophan, and valine) or containing nine exogenous amino acids with removal of any one of the 10 essential amino acids. However, when larvae were reared on diets lacking all eight of the exogenous nonessential amino acids together (alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, and tyrosine), or either glycine or serine, they survived but exhibited significantly delayed larval development. When adults fed on a diet lacking all 10 essential amino acids or all eight nonessential amino acids, no effect on adult survivorship, sexual maturity, or egg hatch was observed, but the fecundity was significantly reduced. Removal of arginine, histidine, isoleucine, leucine, lysine, threonine, tryptophan, methionine, tryptophan, or valine from adult diets decreased fecundity significantly.