The Ralstonia solanacearum species complex has long been recognized as a group of phenotypically diverse strains that can be subdivided into four phylotypes. Using a polyphasic taxonomic approach on an extensive set of strains, this study provides evidence for a taxonomic and nomenclatural revision of members of this complex. Data obtained from phylogenetic analysis of 16S rRNA gene sequences, 16S-23S rRNA intergenic spacer (ITS) region sequences, partial endoglucanase (egl) gene sequences and DNA-DNA hybridizations demonstrate that the Ralstonia solanacearum species complex is comprised of three genospecies. One of these includes the type strain of R. solanacearum and consists of R. solanacearum phylotype II strains only. The second genospecies includes the type strain of R. syzygii and contains only phylotype IV strains. This genospecies is subdivided into three distinct groups, namely R. syzygii, the causal agent of Sumatra disease on clove trees in Indonesia, R. solanacearum phylotype IV strains isolated from different host plants mostly from Indonesia, and strains of the blood disease bacterium (BDB), the causal agent of the Banana Blood Disease, a bacterial wilt disease in Indonesia affecting bananas and plantains. The last genospecies is composed of R. solanacearum strains belonging to phylotypes I and III. As these genospecies are also supported by phenotypic data that allow the differentiation of the three genospecies, the following taxonomic proposals are made: emendation of the descriptions of R. solanacearum and R. syzygii, descriptions of Ralstonia syzygii subsp. syzygii (R 001T = LMG 10661T = DSM 7385T) for the current R. syzygii strains, Ralstonia syzygii subsp. indonesiensis subsp. nov. (UQRS 464T = LMG 27703T = DSM 27478T) for the current R. solanacearum phylotype IV strains, Ralstonia syzygii subsp. celebesensis subsp. nov. (UQRS 627T = LMG 27706T = DSM 27477T) for the BDB strains and Ralstonia pseudosolanacearum sp. nov. (UQRS 461T = LMG 9673T = NCPPB 1029T) for the R. solanacearum phylotype I and III strains.