The aim of this study is to describe the characteristics of caregivers of chronic hemodialysis patients, assess their perceived burden and health-related quality of life, and investigate factors influencing this burden. We studied 100 hemodialysis patients and their respective primary caregivers for more than 4 months, measuring quality of life by the Medical Outcomes Survey 36-item Short-Form Health Survey (SF-36). Subjective burden on caregivers was assessed by the Caregiver Burden scale (score range, 1 to 4; higher values indicate a greater effect). The majority of caregivers were women (84%), married (66%), with a mean age of 46 +/- 2 (SE) years, and of low socioeconomic level. Their main types of relationship with patients were wives (38%) and sons or daughters (27%). Caregiver Mental Health and Vitality were the most affected emotional dimensions on the SF-36 (mean scores, 64.4 +/- 1.8 and 66.6 +/- 1.7, respectively). Mean score of total burden experienced was 2.07 +/- 0.05. Multiple regression analysis showed that independent and significant predictors of burden were Mental Health of the caregiver (R-2 = 24%), Vitality of the patient (R-2 = 10%), type of relationship of the caregiver (female spouse) (R-2 = 5%), and Pain of the caregiver (R2 = 3%). Caregivers of hemodialysis patients may experience a significant burden and an adverse effect on their quality of life. Emotional aspects of caregivers (particularly female spouses) and patients are important predictors of burden. Social support and psychological interventions should be considered to improve caregiver life and patient outcomes. (C) 2002 by the National Kidney Foundation, Inc.