Objective: The purpose of this study was to investigate the cognitive function and social cognition affecting the social participation of patients with Mild Cognitive Impairment(MCI). Methods: 32 MCI subjects were selected through the Cognition Scale for Older Adults(CSOA), and we administered a Faces test, Picture sequencing test, Social Skills Scale(SSS), and the Independent Living Skill Survey(ILSS) for collecting data on social cognition and Korean Activity Card Sort(K-ACS) for social participation. For the data analysis, we implemented a descriptive statistic, a pearson correlation coefficient and a multiple regression analysis. Results: This study shows that social participation in MCI patients correlates with Full scale IQ(FIQ), Basic IQ(BIQ), Executive IQ(EIQ), Working Memory Index(WMI), Visuospatial Function Index(VFI), Memory Function Index (MFI), and Mini Mental State Examination-Korean version 1(MMSE-K1). EIQ and FIQ were more significant factors than other cognitive functions. In social cognition, we found that social participation in MCI patients correlates with the Faces test, Picture sequencing test, SSS, and the ILSS. Emotion recognition and interpersonal relationship were more significant factors affecting social participation. Conclusions: Intervention for social participation in MCI patients is needed to systematic approach of cognitive function and social cognition. In particular EIQ, FIQ, emotion recognition, and interpersonal relationship should be considered.