The complete amino acid sequence of lysozyme-1 purified from pheasant egg white was determined by automatic and manual Edman degradation of peptides obtained from Staphylococcal protease and trypsin digestions. Although three molecular species of lysozyme were found in the pheasant egg white, only one molecular species, lysozyme-1, was sequenced in this study. Pheasant egg white lysozyme-1 (PEL-1) consisted. of a single polypeptide chain of 129 amino acid residues. The presented sequence of PEL-1 was compared with that of hen egg white lysozyme (HEL). There were 17 unique replacements, i. e., Ala 10, Gly 16, Ala 32, Lys 33, Phe 34, Asn 37, Asp 46, Asn 48, Arg 68, Arg 73, Leu 75, Asn 77, Ala 82, Ser 85, Ser 91, Asn 93, and Lys 96 in the sequence of HEL were replaced by Val 10, Ser 16, Vai 32, Asn 33, Trp 34, Gly 37, Asn 46, Asp 48, Lys 68, Lys 73, Phe 75, Ala 77, Leu 82, Asn 85, Ala 91, Arg 93, and Tyr 96 respectively, in that of PEL-1. Extensive structural homology was observed among the two enzymes.