The composition and distribution of Pseudo-nitzschia species in the coastal waters of the Far Eastern seas of Russia are not clear because Pseudo-nitzschia has often been identified only to the genus level. Electron microscopy observation revealed the presence of potentially toxic diatoms in the genus Pseudo-nitzschia on the Russian east coast. These species were Pseudo-nitzscia pungens, P. multiseries and P. pseudodelicatissima. P. pungens and P. multiseries are the most common and widely distributed species. They are abundant in the spring-summer period on the west coast of Bering sea and Kamchatka and in the coastal waters of Sakhalin island. The number of those species varied from dozen up to hundred of thousands cells per liter. The regular outbursts of Pseudo-nitzschia multiseries/ P. pungens (106cell×l-1) are recorded every year in June and September in the coastal waters of the Sea of Japan. P. pseudodelicatissima was found only in the coastal waters of the Sea of Japan and Sakhalin island. It is most common during mid- to late summer (104-105 cell×l-1). Dispersal mechanisms for Pseudo-nitzschia species are not known for the coastal waters of the Far Eastern seas of Russia. The wide distribution and ability to form blooms is probably explained by existing of resting stage in the life cycle of these species. According to the investigations of P. pungens in laboratory culture, these species can produce resting cells. It is supposed, that resting cells may be transported by currents or ballast water and survive until conditions are favorable for germination.