This paper presents new empirical evidence on the effects of retirement benefits on labor force participation decisions. We use administrative data on the census of private sector employees in Austria and variation from mandated discontinuous changes in retirement benefits from the Austrian pension system. We present nonparametric, graphical evidence documenting labor supply responses to the policy discontinuities. Next, based on the nonparametric evidence and mandated financial incentives, we estimate extensive margin labor supply elasticities. We estimate elasticities of 0.12 for men and 0.38 for women. The evidence indicates these elasticities are primarily driven by substitution effects rather than wealth effects.