The amino acid contents of some feedstuffs were determined at the Livestock Experiment Station in 1971. The ground samples which include about 30㎎ protein were placed in special glass bottles, and 200-400 times 6 N-HCl solution was pipetted in each bottle. They were freezed by liquid nitrogen, vacuumed by a rotary pump, sealed by a propane-gas burner, and digested in a 110℃ oven for 24 hours The adequate amount of filtered amino acids mixture was analyzed for other ammo acids than cysteine and methionine by long and short columns of Hitachi KLA-3B Amino Acid Autoanalyzer. In order to measure the contents of cysteine and methionine, they were synthesized into cysteic acid and methionine sulfone with the aid of performic acid preceeding the process of HCl digestion. The two amino acids were analyzed through only short column. The results obtaimed were generally similar to those published abroad previously. However, some feedstuffs or some amino acids showed a few different figures from foreign data. It seemed that more analysis for each feedstuff would be necessary for deciding whether this difference between home and foreign results be reasonable or not.