This article reports on a study of the impact of unemployment duration on the probability of becoming a social assistance recipient and on the time spent on social assistance. The data are taken from a local Finnish labour market consisting of the cohort of unemployed people at a given date (n = 2,274). The data are linked to information about the number of months recipients received social assistance during the subsequent year. Count data regression models of the hurdle type are estimated. The results of the analysis suggest that the impact of unemployment duration on the probability of becoming a social assistance recipient is explained to a large extent by changes in the distribution of types of unemployment benefits between people with different lengths of time spent in unemployment. Unemployment assistance recipients are more likely to become social assistance recipients and to spend longer periods on social assistance than are recipients of unemployment insurance because the unemployment benefits for the latter are higher. Among social assistance recipients, time spent on the transfer increases with unemployment duration only for those who are in frequent need of assistance.