The genus Corallococcus was separated from the genus Myxococcus mainly on the basis of differences in morphology and consistency of swarms and fruiting bodies of the respective members. Phylogenetic, chemotaxonomic and physiological evidence is presented here that underpins the separate status of these phylogenetically neighbouring genera. Emended descriptions of the two genera are presented. The data also suggest that the species Corallococcus macrosporus belongs to the genus Myxococcus. To the best of our knowledge, the type strains of the species Myxococcus macrosporus and Myxococcus stipitatus are not available from any established culture collection or any other source. A Request for an Opinion is made regarding the proposal that strain Cc m8 (=DSM 14697 =CIP 109128) be formally recognized as the neotype strain for the species Myxococcus macrosporus, replacing the designated type strain Windsor M271T, and that strain Mx s8 (=DSM 14675 =JCM 12634) be formally recognized as the neotype strain for the species Myxococcus stipitatus, replacing the designated type strain Windsor M78T.