The clinical-genealogic and molecular-genetic investigation of oculopharyngeal muscular dystrophy (OPMD) in the Republic of Sakha (Yakutia) was performed. it was investigated 33 unrelated yakut families with 38 patients and 2 russian families with 2 patients and 59 their healthy relatives as well. The high clinical polymorphism of disease was found in patients with OPMD. The mutation in exon 1 of the PABPN1 gene resulting in the expansion of GCG-repeats up to 10 is revealed. Using direct sequencing of the PABPN1 gene in 17 families (16 yakut, 1 russian), we identified a type of this mutation as an insertion of 4 GCG-repeats. Frequency of OPMD in the yakut population is 1:11 680 that is 10-20 times higher comparing to european populations. This is a first report on the patients with OPMD from the Republic of Sakha with diagnosis confirmed by molecular-genetic analysis.