Clostridium aurantibutyricum , Clostridium felsineum and Clostridium roseum share a very high similarity based on multi-locus sequence analysis. In this study, their correct taxonomic status was determined using genomic and phenotypic investigations. Average nucleotide identity based on MUMmer alignment of the genomes and in silico DNA–DNA hybridization resulted in values of 98.55–100 and 78.7–100 %, respectively, strongly indicating that all strains are members of the same species. In addition, morphological investigations, fatty acid analyses and substrate utilization tests revealed no striking differences between the strains. Therefore, we propose the reclassification of C. aurantibutyricum and C. roseum as later heterotypic synonyms of C. felsineum . The type strain is lodged in several culture collections (ATCC 17788T=DSM 794T=NCIMB 10690T).