Countercurrent distribution separated rhesus monkey hemoglobin into α and β polypeptide chains, which were respectively oxidized with performic acid, dissolved in 8 M urea to be denatured at 60° for 45 min, and then digested with pepsin at 37° for 2 hours. Peptic peptides thus obtained from each polypeptide chain were isolated and purified by column‐ and by paper chromatography, and the amino acid composition of each peptide was analyzed. Sequence analysis was carried out by using PTC and DNP methods, if necessary.From the results thus obtained, the present authors established the primary structure of rhesus monkey hemoglobin, taking account of the amino acid sequence in all the tryptic peptides from the α and β polypeptide chains previously r