Past examinations of the impact of chronic illness on identity have focused primarily on positive adaptation (i.e., benefit finding or posttraumatic growth). Given that associations between these constructs and psychosocial wellbeing are equivocal, greater investigation is needed into interactions among perceived positive and negative identity changes pursuant to illness. A cross-sectional study was conducted between 2006 and 2007 with an ethnically diverse sample of 129 HIV-positive gay and bisexual men. Participants completed a brief quantitative survey, including a new measure, the Impact on Self-Concept Scale (ISCS), as well as gay-related stigma, quality of life, and regulatory focus. Factor analysis supported the existence of two ISCS subscales: self-growth and self-loss. Both subscales demonstrated strong internal consistency and were weakly but positively correlated. Preliminary assessment of construct validity indicated distinct patterns of association, with self-loss being more strongly associated with stigma and quality of life than self-growth. In multivariate models, associations between self-loss and both quality of life and regulatory focus were moderated by self-growth. The ISCS demonstrated preliminary reliability and validity in this sample. Findings suggest that self-growth and self-loss are meaningfully distinct constructs that may interact to produce important implications for understanding the experience of chronic illness.