The aim of this study was to examine whether formal support and coping would mediate the effects of primary stressors and caregiver characteristics on three stress outcomes: yielding of role, anxiety, and physical health. Secondary analysis of longitudinal data from a convenience sample of 452 spouse and adult child caregivers of Alzheimer's patients was used for model testing. Path analysis suggested that decreased physical health of the caregiver was best explained by caregiver overload. Caregiver anxiety was explained by lower levels of care receiver dependency, higher levels of caregiver overload, and higher levels of caregiver anxiety measured 1 year earlier. Yielding of the caregiver role was explained by the direct effect of higher levels of care receiver problem behaviors as well as more use of formal supports. Spouse relationship had a negative effect and care receiver dependency had a positive effect on yielding of the role through the mediating influence of formal support. Neither coping nor formal support mediated primary stressors and caregiver characteristics in the directions hypothesized.