Objectives: Little research has investigated the relationship between types of leisure activities and mental health outcomes among older adults with mild cognitive impairment (MCI). The purpose of this study was to investigate how certain leisure activities are associated with life satisfaction, anxiety, loneliness, happiness, and positive and negative affect. Methods: In this study, we used the 2020 Health and Retirement Study Core Early data and conducted a hierarchical regression analysis to investigate the different effects of the 3 types of leisure activities on the mental health of older adults with MCI (N=901). Results: We found that leisure-time physical activity was the strongest predictor of enhanced life satisfaction, positive affect, and happiness, and reduced anxiety and loneliness. In addition, sedentary leisure was associated with reduced anxiety and loneliness and increased happiness. Conclusions: These findings suggest that engagement in leisure-time physical activity and sedentary leisure can be instrumental in promoting the life satisfaction and mental health of older adults with mild cognitive impairment.