The AIDS epidemic and the growing social enfranchisement of sexual minorities over the past three to four decades has had a profound impact on the lives of the current cohort of midlife and older gay-identified men (hereinafter, gay men), yet little is known about how the general health status of these men has developed over this time. The proposed exploratory study (a) will analyze 27 years of health and psychosocial data from an existing sample of HIV- and HIV+ midlife and older gay men (b) in conjunction with new data from this sample to be collected with the Aging, Stress, and Health among Gay Men (ASH-GM) survey. The sample is the original cohort of the Los Angeles (LA) site of the Multicenter AIDS Cohort Study (MACS, current N = 400; mean age=57, range=43-79). Begun in 1984, the MACS are one of the longest running natural history studies of HIV/AIDS. These data are especially valuable because multiple biopsychosocial domains have been measured biannually since the study's inception, providing a unique data repository that serves as the foundation for innovatively studying aging processes among gay men from a life course perspective. We propose to further develop and test a novel life course and sexual minority aging stress model, integrating (I) the life course perspective (e.g., trajectories, transition, turning points); (ii) the general stress process model (e.g., financial strain, psychosocial resources); (iii) the minority stress model (e.g., stigmatization); and (iv) aging-related stressor (e.g., independence concerns). A key feature of this conceptual model is the intersection of history with individual biography. The life course concept of trajectories will be operationalized as a latent class mixture model to create clusters of similar trajectories with the 27 years of longitudinal data for two prototypes: health (depressive symptoms, cardiovascular disease) and psychosocial resources (having a confidant). The test of the theoretical model first examines the impact of the types of stressors listed above with current health status, along with the mediating and moderating role of psychosocial resources. This conventional approach is then innovatively elaborated by examining the main and interactive effects of the trajectories to test whether the impact of current conditions on health is conditional upon the past. Due to the dearth of longitudinal data on sexual minorities, research using a life course perspective to study aging among this population will necessarily rely on retrospective data. We will innovatively evaluate such retrospective reports by exploiting the longitudinal design of the MACS to compare reports made at the time to new retrospective reports of the same constructs collected with the ASH-GM. Our specific aims are to: (1) design and implement the ASH-GM; (2) analyze 27-year trajectories with existing MACS-LA data; (3) test the novel theoretical model using both sets of data; and 4) evaluate the use of retrospective reports to study the life course of midlife and olde gay men. Findings will be informative to emergent research on aging among these men, and will provide preliminary data for an RO1 application that will longitudinally expand this exploratory study to all four MACS sites.