Health-related quality of life (HRQOL), a validated system of measuring patients' physical, mental, and social well-being, can be of particular use in populations with chronic conditions, such as end-stage renal disease (ESRD). The Dialysis Outcomes and Practice Patterns Study (DOPPS) has used the Kidney Disease Quality of Life Short Form (KDQOL-SF) to measure ESRD patients' self-assessment of functioning and well-being, as measured by 3 component scores: physical component summary (PCS, 4 subscales), mental component summary (4 subscales), and kidney disease component summary (11 subscales). Several DOPPS studies examined HRQOL's associations with mortality and hospitalization by country, ethnicity (United States only), and in comparison with serum albumin levels; international variations in HRQOL of ESRD patients were also evaluated. Lower scores for all 3 summary scores were strongly associated with higher risk of death and hospitalization; these measures, especially PCS, may better identify patients at risk for death and hospitalization than serum albumin level. Japanese patients reported a greater burden of kidney disease but higher physical functioning than patients in Europe or the United States; many other significant regional differences in HRQOL were found. In the United States, all summary scores were significantly associated with mortality risk, regardless of ethnicity. Compared with whites, blacks had higher scores for all 3 summary scores, Asians and Hispanics had higher PCS scores, and Native Americans had lower mental component summary scores. Among ESRD patients, HRQOL displays an important predictive power for adverse events. Identifying effective interventions to improve the HRQOL of patients with ESRD should be viewed as a valued health care goal.