This paper provides the first experimental evidence on the long-term effects of work-study programs, leveraging a randomized lottery design from a national program in Uruguay. Participation leads to a persistent 11 percent increase in formal labor earnings seven years after the program, driven by a 4 percent increase in the monthly probability of being employed and a 6 percent increase in monthly wages. Effects are significantly larger for men, while remaining positive for women. The program is highly cost-effective, outperforming most job training programs and reaching levels comparable to early childhood investments.