The results of serologic survey of 4118 residents of the USSR Far East from 16 to 82 years of age and 1037 blood donors for antibody to HTLV-I by the method of passive agglutination of gelatin particles coated with viral proteins are summarized. The portion of HTLV-1 seropositive subjects in the Khabarovsk Territory was 1.79% (25 out of 1391), in the Maritime Territory 2.2% (18 out of 801), in the Sakhalin Island 1.6% (26 out of 1557), and in Kamchatka 1.6% (6 out of 369). A discrete area of a higher number of positive cases was found among Nivkhi national group in the village of Nogliki in the Sakhalin Island: 6.4% (10 out of 155). In women, antibody to HTLV-1 was found twice as frequently as in men. Seropositives to HTLV-1 among blood donors in Moscow, the town of Komsomol'sk-na-Amure, and the town of Yuzhno-Sakhalinsk comprised 1.4%, 1.6%, and 5.45%, respectively. The occurrence of HTLV-1 infection among the normal population of the Far East and especially among blood donors attests to the expedience of wider seroepidemiological surveys of the population and especially donors for HTLV-I infection in other regions of the USSR as well.