Displaced workers often experience large losses in earnings even a long time after reemployment. Training programs during unemployment mitigate these losses but also a¤ect the unemployed's willingness to search. This paper analyzes how mandatory training programs a¤ect the optimal design of unemployment insurance and how the training intensity should evolve during the unemployment spell. The introduction of training reverses the optimal consumption dynamics during the unemployment spell and makes it optimal to incentivize the long-term unemployed to …nd employment despite the depreciation of their human capital. Targeting training programs towards the long-term unemployed, however, is optimal only if the fall in human capital upon displacement is small relative to the depreciation during unemployment.Keywords: Unemployment, Optimal Insurance, Human Capital, Training JEL Classi…cation Numbers: H21, J62, J64I would like to thank Arthur Campbell, Peter Diamond, Florian Ederer, Jesse Edgerton, Bengt Holmström, Henrik Kleven, Gerard Padró i Miquel, Frans Spinnewyn, Ivan Werning, the editor, three anonymous referees, and seminar participants at MIT, Warwick University and the EEA-ESEM meetings for many helpful comments and suggestions.