Purpose: Researchers' knowledge regarding older users of illicit drugs is limited despite the increasing numbers of users. In this article, we apply a life course perspective to gain a further understanding of older adult drug use, specifically contrasting early- and late-onset heroin users. Design and Methods: We collected qualitative data from 29 older heroin users. Life course analysis focused on the users' experiences across the life span. Results: The findings suggest that those aging into heroin use (late onset) are disadvantaged compared to those who are maturing in (early onset) except in areas of health. Implications: We propose that conceptualizing the use of heroin and other illicit drugs among older adults based on the user's life course trajectory will provide insights for social and health services, including drug treatment.