Differences in molecular weights and partial amino acid sequences of connectin(titin) were determined for cattle, pig and chicken skeletal muscles. Peptide mapping analysis results differed according to animal species. Amino acid sequences deduced from partial nucleotide sequences of connectin also differed according to animal species at immunoglobulin-like (Ig) and fibronectin type 3 (FN3) domains. In chicken, the molecular weight of connectin from leg muscles was higher than that from pectoral muscles. Differences in meat texture and conditioning may relate to connectin and extent of its breakdown.