Meno who have sex with men (MSM) and who inject drugs (IDU) have not received the same degree of research attention as other drug users. In light of current HIV seroprevalence statistics regarding MSM, and in particular IDU MSM, we propose to conduct a two city (Seattle, Washington and Denver, Colorado) comparative ethnographic study focusing on MSM who use drugs, and particularly those who are dual risk for HIV through both sexual behavior and injection drug use. A particular focus will be the use of methamphetamines and the evidence that this drug in this population may pose special risks for HIV transmission. This proposal explicitly builds on the current NIDA exploratory study of IDU MSM (R03 DA10206-01) in Seattle and is submitted in response to NIDA PA announcements 95-057 (HIV Risk Behaviors, Determinants and Consequences) and 93-098 (Drug Abuse Aspects of AIDS). A primary contribution of recent ethnographic research among IDUs has been to uncover and descirbe the multiple contextual dimensions influencing drug use and HIV transmission. Ethnography's emphasis on direct observation among IDUs in the natural settings where they carry out their daily activities and interviewing techniques that allow for the subject to give detailed information and for the researcher to probe for additional information, have enabled ethnographers to provide rich data about conditions and circumstances which affect IDUs health. In that, IDU MSM represent an as yet understudied group at elevated risk of HIV nationally. Our research objectives are: 1) to produce a comparative ethnography of drug use including identifying social groups of users and the risk activities they engage in and 2) to gather baseline data for the development of intervention models sensitive to the particular risk groups and behaviors of IDU MSM, especially for those engaging in multiple risk behaviors.