Peptide fingerprints of tryptic digests of globins of 6 venomous snakes representing 2 families and 3 subfamilies were compared. The evolutionary relationships of these snakes derived from globin peptide fingerprints are consistent with those based upon morphological criteria. Globins of Trimeresurus mucrosquamatus and Trimeresurus s. stejnegeri are most alike, differing in 19 components. The average from globins of the 2 Trimeresurus compared with Agkistrodon shows a difference of 24 components. The average difference between the 3 crotalines and Vipera is 26. Naja globin is most divergent in structure, differing from those of the 4 viperids by 42-44 peptides, and from that of Bungarus by 32 peptides.