We studied the karyotype of the frog sculpinMyoxocephalus stelleri Tilesius (Cottidae) from Peter the Great Bay: 2n=40; NF=46. In the series of two-armed chromosomes, there is a pair of large submetacentric ones, while there are two pairs of large subtelocentric chromosomes in the one-armed series. Ag-NOR staining revealed nucleolus organizer regions in the short arms of two pairs of subtelocentric chromosomes that differed in size. We found neither differences between male and female karyotypes nor variability of any type. The karyotype ofM. stelleri is compared with that of the short-spined sea scorpionM. scorpius.