Routine activity theory and lifestyle-exposure theory propose that victimization rates differ across demographic groups because individuals in these groups engage in different activities. This implies that routine activities mediate the relationships between demographic characteristics and victimization. Although this core assumption underlies both theories, few researchers have attempted to test its validity, and the tests that do exist have relied primarily on cross-sectional, nongeneralizable data. The current study examines how routine activities mediate the associations between four demographic characteristics (gender, age, marital status, and household income) and violent victimization and theft using a longitudinal data set created from the National Crime Victimization Survey. We combine a multivariate ordered logistic model with a general structural equation model to examine direct and indirect paths. Results indicate that the effects of gender, income, and marital status on victimization are each at least partially mediated by routine activities, suggesting the applicability of lifestyle theories to the study of victimization.