F ULL details of the age-sex structure of the Soviet Union were published only for 1926 and are now out-dated by over a quarter of a century. From the 1939 All-Union Census only partial data were published, and the form in which this material was published suggests that the Soviet Government may have been interested in suppressing factual information about certain aspects of the population structure. It is the purpose of the present paper to show in broad groupings the 1939 age-sex composition of the USSR total, urban, and rural population. The method used in calculating the three age-sex compositions is described in the pages that follow. It is hoped that this material will not only increase the knowledge of the Soviet Union's 1939 population, but also-in view of the extensive use made by scholars of the 1939 partial data as a basis for making 1950-1970 population projections-contribute to a better understanding of the USSR's population at present and in the immediate future. In 1940 the Soviet government published a preliminary tabulation from the 1939 AllUnion Census showing the distribution of 99.44 per cent of the population among certain age classes, but with no indication of the sex ratios of the population within these age classes. (See Table 1A.) A tabulation for the entire population was never published, although complete totals were announced. (See Table 1B.) In his book, published in 1946, Frank Lorimer worked out in an ingenious way an age and sex distribution for the Soviet Union, piecing together the fragments of published data but relying heavily on the judicious use of projection and other demoTABLE 1. POPULATION OF THE USSR (According to the 1939 Census)