Аннотация:Previously accepted subfamily Scaphirhynchinae included two genera: Scaphirhynchus in North America and Pseudoscaphirhynchus in Central Asia. Among three known Pseudoscaphirhynchus species only the Amu Darya sturgeon, P. kaufmanni, more or less often occurs in the catch now. This species is represented by two forms with unclear taxonomic relations: normal and dwarf forms. The karyotypes of Pseudoscaphirhynchus species were never studied before. In recent study the karyotype of the dwarf form of P. kaufmanni is described at first. Cells of the head lymphoid organ were subjected to karyotypic analysis using previously published method (Vasil’ev & Sokolov 1980). 14 methaphase plates from three specimens collected in the Vakhsh River (Amu Darya tributary) were analyzed. The karyotype consists of 116-120 chromosomes; the number of large bi-armed chromosomes is 20, first of them are metacentrics; the number of small bi-armed chromosomes is 32; there are only two large acrocentrics, whereas the rest 62-66 chromosomes are small acrocentrics or microchromosomes. This karyotype is similar to ones of 120-chromosome Acipenser species, and demonstrates significant differences from the karyotype of Scaphirhynchus platorhynchus. The last karyotype includes six large acrocentrics, and the first largest chromosomes in this karyotype are submetacentrics (Onho et al. 1969).