This chapter discusses several testable implications of Lazear's (1979) model of mandatory retirement and tests whether they are consistent with the data, using a sample from the National Longitudinal Survey of Mature Men. Empirical evidence on the close association between firm pension programs and mandatory retirement programs can be interpreted to lend support to Lazear's model. However, estimates from an econometric model of retirement behavior reject an important implication of the model concerning the relationship between mandatory retirement and the propensity to retire early.