The spectrophotometric determination of hydroxylamine, glycine and methionine has been investigated. The high molar absorptivity of the investigated amino acids or hydroxylamine-nitroprusside complexes at the optimum conditions indicates that concentrations of 10−4−10−3M of these compounds can be determined spectrophotometrically with fair accuracy. The effect of pH was studied and the optimum pH was chosen to give the highest sensitivity. The validity of this method is supported by the constancy of the absorptivity of the investigated compounds and the statistical data of regression analysis.