Based on the results of phenotypic characterization, cellular lipid and fatty acid analysis, phylogenetic analysis of 16S rDNA nucleotide sequences and rNA-DNA hybrization, Burkholderia pickettii, Burkholderia solanacearum and Alcaligenes eutrophus are transferred to the new genus Ralstonia, and Ralstonia pickettii (Ralston, Palleroni and Doudoroff 1973) comb. nov., Ralstonia solanacearum (Smith 1896) comb. nov., and R. eutropha (Davis 1969) comb. nov. are proposed. The type species of the new genus is R. pickettii. Type strain of R. pickettii is ATCC 27511T, of R. solanacearum is ATCC 10696T, and of R. eutropha is ATCC 17697T.