It was generally known, that as a consequence of the World War Two, party terror and mass deportations Byelorussia suffered severe population losses. But only after the figures of the 1959 census were published was it possible to give these losses in more exact numbers. The Sowjet census of January 15, 1959 found the population within the borders of the Byelo­russian SSR to be 8 055 000. Twenty years before, at the beginning of 1939, within the same territory there lived a population of 9 344 000. This indicates a decrease of 1 289 00, or 13.4%. While publishing figures of the last census the Central Statistical Office of the USSR gave for 1939 the lower figure of 8 910 000 with apparent aim to conceal the extent of depopulation in the republic. All previously published Sowjet population figures for the same territory in 1939 were much higher than 8 910 000. It is important to keep in mind, that the decrease of 1 289 000 does not reveal all the actual demographic losses. Also the normal expected natural yearly increase of population disappeared entirely. The typical rate of the yearly natural population growth in Byelorussia in the 20th Century was 2°/o. On this basis from 9 344 000 of 1939 in 1959 we would expect 13 878 000, and with an addition of 222 000 known immigrants for the same period of time, even 14 100 000. Since the census revealed only 8 055 000, it means, that the twenty years demographic deficit of the republic is 6 045 000. One third of that, 2 000 000, are direct or indirect World War Two lo