Although prolonged exposure therapy (PE) is considered an evidence-based treatment for PTSD, there has been little published about the use of this treatment for older adults with comorbid early-stage dementia. As the number of older adults in the United States continues to grow, so will their unique mental health needs. The present article describes the successful coordination of care and application of PE in the assessment and treatment of a Vietnam veteran with comorbid PTSD and early-stage dementia. Measures related to the patient's cognitive and psychological functioning were obtained before, during, and after treatment. PE was associated with significant declines in PTSD and depression symptoms. Moreover, the patient's cognitive functioning was made clearer in the absence of severe psychiatric symptoms. Factors contributing to the patient's positive response are discussed.