The European mink Mustela lutreola is one of Europe's most endangered carnivores, with few vulnerable populations remaining. Surprisingly, a recent phylogeny placed a single mink specimen within the polecat (M. putorius, M. eversmannii) group, suggesting a recent speciation and/or the effects of hybridization. The analysis has now been extended to a further 51 mink and polecats. As before, phylogenetic methods failed to resolve the relationships between the species. One haplotype (C11) was found in both species, and predominated in European mink from Spain and eastern Europe. The known M. lutreola fossils are of very young date, so either mink arose recently, or else the situation is confused by hybridization and a biased fossil recovery. The study highlights the dangers of using a single genetic marker in defining Evolutionarily Significant Units (ESUs). Polecats and European mink are clearly distinct in their morphology and ecology, and should still be considered as separate ESUs, but without further data it is difficult to define Management Units. Following the precautionary principle, we recommend that for the moment European mink in eastern Europe (Belarus, Estonia and Russia) and Spain should be managed separately.