In consideration of the criticisms of the transfer of Pseudomonas maltophilia to the genus Xanthomonas proposed by J. Swings, P. De Vos, M. Van den Mooter, and J. De Ley (Int. J. Syst. Bacteriol. 33:409-413, 1983), a new generic name is created for this taxon. The name Stenotrophomonas is here proposed for the new genus, which includes a single species, Stenotrophomonas maltophilia. This proposal restores the genus Xanthomonas to its former definition (J. Bradbury, p. 199-210, in N. R. Krieg and J. G. Holt, ed., Bergey's Manual of Systematic Bacteriology, 1984) The arguments on which this proposal is based are presented.