Phylogenetic analysis including morphological data, as well as matK and 5.8S and flanking ITS sequences suggests that Phaseolus is monophyletic and most closely related to genera of New World Phaseolinae. Comprehensive taxon sampling of wild and cultivated species reveals seven major lineages within the Phaseolus radiation. The five cultivated species come from two of these. Phaseolus acutifolius, P. vulgaris, P. coccineus, and P. polyanthus form the syngameon clade, and P. lunatus is part of a clade that includes the only major South American radiation in the genus. Previously proposed sectional classfications of the genus are emended to meet the criterion of monophyly.

Key words: classification, Fabaceae, Phaseolus, phylogenetics