Routine activities theory and lifestyle theory propose that victimization rates differ across demographic groups because individuals in theses groups engage in different activities. Although this core assumption underlies both theories, few researchers have attempted to test its validity. Unlike past studies, which have used cross-sectional, non-generalizeable data with limited measures of routine activities, I examine this issue using a longitudinal dataset created from the National Crime Victimization Survey that includes additional routine activities not considered in previous work. The current study examines how routine activitiesriding public transportation, attending work or school, going shopping, or going out at nightmediate the associations between demographicsage, gender, socioeconomic status, and marital statusand personal victimization. The results suggest the effects of gender, income, and marital status on victimization are mediated by routine activities. I discuss the theoretical implications of these findings for future research on the relationship between lifestyles and victimization.