The taxonomic position of aerobic bacteriochlorophyll a-containing bac
teria (erythrobacteria) was determined based on comparative analysis o
f 5S rRNA sequences. Erythrobacteria proved to form a specific cluster
within the alpha-subclass of proteobacteria. The generic status of Er
ythromicrobium and Roseococcus was confirmed. The obtained data also c
onfirm the existing classification of all described species of freshwa
ter erythrobacteria.