The current study examined professional caregivers' perceived and physiological stress, and associations with the quality of care they provide. Participants were 55 female caregivers from childcare homes and 46 female caregivers from childcare centers in the Netherlands. In both types of settings, equivalent measures and procedures were used. On non-work days, caregivers' salivary cortisol levels decreased between 11 am and 3 pm, whereas on work days, caregivers' cortisol levels remained at the same level during this period. Caregivers' cortisol levels and perceived stress did not differ across the two types of settings. In home-based childcare, caregivers offered higher-quality caregiving, compared to caregivers in center-based childcare. In home-based childcare--but not in center care--caregivers' negative appraisal was associated with less positive caregiver behavior. These findings suggest that work at childcare influences cortisol secretion in professional caregivers, and that perceived stress but not cortisol is associated with quality of care. (Contains 3 tables and 2 figures.)