This study investigated the prevalence of depression and health problems in caregivers for the disabled elderly at home, and identified factors associated with the risk of depression. Four hundred thirty-four caregivers for disabled elderly persons in a suburban city were surveyed by in-home interviews. Two hundred ten non-caregivers were also interviewed as an age and gender-matched control group. Overall, 16.8% of caregivers met the DSM-III-R criteria for major depression and 10.6% met the criteria for depressive disorders not otherwise specified, for a total of 27.4% meeting the criteria for affective disorders, while 8.6% of controls met the criteria for depressive disorders not otherwise specified. The prevalence of major depression in caregivers was associated with mental problems and ADL limitations of the elderly. Moreover, non-cooperation by other family members or relatives contributed to an increase in the prevalence of depression. Caregivers who met the criteria for major depression had a higher frequency and longer duration of upper respiratory infections than other caregivers or controls, and showed greater fatigue than the other caregivers or controls. Approximately 90% of caregivers who met the criteria for major depression had also insomnia. Overall, it was shown that caregivers who met the criteria for major depressin had not only emotional distress but also higher morbidity.