Recent epidemiological data show that older adults comprise a growing age group of drug users and new AIDS cases in the United States. Prevention and intervention studies show that risk behaviors leading to HIV infection are increasing among older users, particularly among the socially vulnerable. Yet older adults remain an under-researched population of drug users and little is known about their risk behaviors. Our aim is to address this gap in knowledge on older users by comparing contextual factors that influence risk behaviors and harm reduction strategies practiced by older drug users living in different communities. This study is based on ethnographic fieldwork in suburban and inner-city neighborhoods in a large metropolitan area in the southeastern USA. Interviewers conducted face-to-face, in-depth, life-history interviews with 69 older adults (age 45 and older) who used heroin, cocaine, and/or methamphetamine. Findings show that while risk behaviors were similar among older adult drug users living in suburban and inner-city environments, the provision of harm reduction education and paraphernalia varied widely. The results show the need for the expansion of harm reduction services focused on older adult drug users who are homeless, uninsured, or socially isolated. This application-oriented research will inform healthcare and treatment providers and generate new directions for future collaborative harm reduction services aimed to decrease the spread of HIV and other infectious diseases associated with drug use (Authors).