DESCRIPTION (Applicant's Abstract): Although we are well into the second decade of the HIV pandemic, there is yet no cure or vaccine. At this time, further spread of HIV may only be deterred through behavioral means. Leading researchers have recommended that innovative strategies must be implemented in order to improve our prevention efforts. The social and/or cultural milieu in which HIV risk behavior occurs has been identified as an important aspect of prevention programs that has been previously underestimated. An intimate relationship is one example of a social milieu wherein risk behavior occurs. Much of the HIV risk behavior literature has focused on the experience of the individual, disregarding the relationship status of the gay men in their samples. Conclusions based on individual reports have not taken into account the influence a partner may have in either increasing or decreasing HIV risk behavior. In order to address some of the above deficits in the literature, this dissertation work proposed will investigate what factors influence HIV risk behavior for gay male couples (both low and high risk behavior). The framework for this investigation is a conceptual model that was developed within the context of women, stress, and heart disease (Chesney & Darbes, in press). The proposed study will empirically validate the model and extend it to the case of HIV risk behavior. Specifically, four mediational models predicting HIV risk behavior will be tested, with a focus on variables shown to be important constructs within the domains of both Health Psychology and HIV/AIDS research: social support, depression, and health behaviors. In addition, an HIV-specific measure of partner support will be compared with a general social support measure, in order to test the hypothesis that a more specific measure of social support will be a better predictor of HIV risk behavior. The sample will be composed of 50 gay male couples, who will complete self-administered questionnaires at three different time points (funding is being requested for the third wave of data collection). Because of the dyadic nature of the data, relationships between the variables will be able to be determined both between and within couples, cross-sectionally and longitudinally. By comparing data between couples the candidate aims to inform our understanding of the social context in which HIV risk behavior occurs and allow us to identify issues pertaining to risk behavior for couples which have heretofore been unknown. Additionally, examining differences within couples could be an important addition to our knowledge regarding risk behavior, as the discrepancy of social support within couples could provide a crucial window of opportunity for intervention. Ignoring this type of contextual influence on HIV risk behavior could render prevention efforts ineffective. In sum, this study examines the possible influences on HIV risk behavior: the social context (in this case, an intimate relationship), depression, social support and adverse health behaviors. The study aims to contribute to the literature on HIV prevention in gay men by filling gaps in the literature regarding the role the above variables may play in HIV prevention, as well as elucidating the influence partners may exert on each other's risk behavior.