Mild cognitive impairment (MCI) is a state of cognitive decline between typical aging and dementia characterized by impaired memory function, particularly for episodic memory—the capacity to mentally relive past experiences—and prospective memory—the ability to recollect future intentions. People diagnosed with MCI are 20-50% more likely to develop dementia over a period of 2 to 3 years. In light of this, finding evidence-based interventions to treat memory deficits among people at risk for MCI is important. Eminent Buddhist scholars and philosophers of mind theorize that mindfulness may facilitate memory, and past research utilizing mindfulness-based interventions have shown treatment effects on autobiographical memory, working memory, and increased gray matter density in brain regions associated with episodic and prospective memory, and MCI-related impairments. The present study takes a levels-of-analysis approach to examine the effect of Mindfulness-Based Stress Reduction vs a structurally equivalent active control intervention on episodic and prospective memory function among aging adults at risk for MCI. The proposed study will measure event-related brain potentials (ERPs) to examine treatment-induced changes in the neural processing of episodic and prospective memory. Event and experience sampling measures will be deployed to capture treatment effects on episodic and prospective memory function as it unfolds in daily life. Analyses will explore whether treatment-induced changes in ERPs are translatable into functional benefits in day-to-day life, as measured by event and experience sampling.