Objectives: The study examined the typical diurnal cortisol trajectory and its differential associations with an intervention, the adult day services (ADS) use, among a sample of family caregivers who experienced high levels of daily stress. Method: On hundred and sixty-five caregivers of individuals with dementia completed an 8-day diary on daily stressors, positive events, sleep quality, and ADS use. The caregivers also provided five saliva samples on each diary day.