Sequences of part of the cytochrome b genes from the cyprinides carp (Cyprinus carpio), bream (Abramis brama), bleak (Alburnus alburnus), chub (Leuciscus cephalus) and lake chub (Rutilus frisii meidingeri) were compared after polymerase chain reaction (PCR) amplification and direct sequence analysis. Together with the published sequences of carp (C. carpio), brown trout (Salmo trutta) and Atlantic salmon (S. salar), the new sequences were used to estimate genetic distances. The five species investigated displayed interspecific variation rather than intraspecific variation. Three of the various point mutations should result in an amino acid exchange in carp, bleak and bream.