The concept, "quality of life" (QOL), offers a broad perspective for assessing the needs and outcomes of chronic mental patients. In this survey of Los Angeles board-and-care homes, 278 randomly selected, mentally disabled residents evaluated their QOL in structured interviews based on a general QOL model. Life areas studied included living situation, family, social relations, leisure, work, safety, finances, and health. The model performed as well among these residents as among the general population, explaining 48% to 58% of the variance in global well-being. Adding patients' subjective QOL evaluations doubled the explanatory power of a model based only on personal characteristics and objective life conditions. Global well-being was most consistently associated with personal safety, social relations, finances, leisure, and health care variables. The study identifies methodological and service issues in need of further examination.