Sequence variation of the 5' end of the mitochondrial DNA control region (600 bp) was examined in the population samples of Eurasian wigeon Anas penelope from Anadyr' and Primorye. A total of 11 different mtDNA haplotypes were identified, with one of these belonging to American wigeon Anas americana. The presence of the mtDNA haplotype from the species closely relative to A. penelope in the Anadyr' sample can be considered as the genetic evidence in favor of interspecific hybridization. This suggestion is in the good agreement with ornithological data. Genetic differentiation of the Primorye and Anadyr' populations was low (phi(ST) = 0.096). The phylogeographic structure was not pronounced.