This article examines the main characteristics of the reform of the Soviet social security system in the 1920s and the early years of Stalinism. It uses an interdisciplinary approach to examine the development of the system from many angles: the beneficiaries, the political debates, and the methods used to finance it. The reforms introduced during this period show that the Soviet welfare system depended almost entirely on economic progress; in 1927, the only state-funded provision was for disabled war veterans. Hence, the welfare system was quite specific: it was used as a tool to promote the industrialization of the country, favouring the workers at the expense of the disabled and unemployed, who were forced to fall back on various self-help strategies, some legal, some illegal. The disabled and unemployed constituted the main social problem of the 1920s. Social legislation between 1931 and 1932, under the shadow of the impact which the Great Depression was having on Soviet society, progressively excluded the disabled and unemployed from the welfare system. Thus the USSR attempted to solve the unemployment problem by means of social exclusion.