In a cross-sectional study, 31 dementia caregivers were compared to a group of 25 noncaregiving controls to evaluate whether the stress of being the primary caregiver of a person with dementia produces cognitive dysfunction. Cognitive differences were examined to evaluate the relationships between cognitive function and stress-related physiological and psychological measures to contribute information regarding its potential mechanism. The cognitive assessments were 2 measures of attention-executive function and 1 word list memory task. Physiological and self-rated stress-related measurements included cortisol, perceived stress, depression, self-efficacy, mindfulness, sleep quality, fatigue, and neuroticism. Caregivers performed worse than noncaregivers on the 2 attention tasks but not on the word list memory test. There was no interaction of caregiver status and age on cognitive performance. The caregivers and noncaregivers differed in morning salivary cortisol and most of the self-rated stress-related measures with the caregiver values reflecting greater stress. Of note, impaired sleep was the only potential mediator of the caregiver effect on cognitive performance in our small sample.