Diversity, its growth and complexity, are defining features of the dramatic aging of the world-wide population. Research demonstrates that older adults from disadvantaged populations are at elevated risk of poor health, disability and premature death. The National Institutes of Health are committed to reducing and eliminating health disparities. The Centers for Disease Control and Prevention state that health disparities related to sexual orientation are one of the main gaps in health disparities research. Existing evidence demonstrates that lesbian, gay and bisexual (LGB) older adults are an at-risk, under-investigated and under-served health disparate population. This study will examine the determinants of health impacting LGB older adults to assess change in health and quality of life (QOL) over time. Based on an innovative resilience conceptual framework, the pro- posed longitudinal research will obtain data from 2,000 LGB older adults who participated in the original study in order to allow us to understand the inter-relationships between risk and protective factors as well as cohort effects as they impact health and QOL of LGB older adults over time. This multidisciplinary collaboration of University of Washington researchers and community-based collaborators addresses a critical gap by identifying modifiable mechanisms impacting health and QOL over time. The primary goals of the project are as follows: 1) Investigate how lifetime victimization, everyday discrimination, stress (perceived stress and physiological response to stress) and health behavior change affects health and QOL of LGB older adults over time; 2) Evaluate how social relations (time-varying) and sexual identity management (time-varying) affect the associations among everyday discrimination, stress, health and QOL over time; and, 3) Test whether there is cohort heterogeneity in overall levels and age growth trajectories of health and QOL, and to what extent the differences in experiences within a historical context (e.g., time of sexual identity disclosure, lifetime victimization) between Baby Boom and Silent Generation LGB older adults account for these cohort effects. As the population ages, the health care costs associated with health disparities will continue to rise. To respond to this growing public health challenge it is imperative to identfy groups at high risk of disparities and to determine the modifiable mechanisms impacting their health and QOL as they age. The findings from this project will generate needed information to directly inform and guide the development of tailored interventions that can be effectively delivered within community-based agency settings to improve the health and QOL of demographically diverse older adults.