Aim(s): Physical and cognitive functioning are both indicators of aging process. Older adults experience abnormal declines in physical and cognitive functioning that increase their risk of dependence, subsequently quality of life. This study aims to explore the relationship between physical and cognitive functioning, and mediation effect of cognitive functioning on the relationship of physical functioning and health-related quality of life among older adults with mild cognitive impairment. Method(s): Seventy-nine older adults living in community participated in the study. Measurements included the self-reported questionnaire for physical functioning consisted of grip strength, one leg standing with eyes open (balance), and Timed Up and Go (mobility). Cognitive functioning was measured by Korean version of MOCA. SF-12 was used to assess physical and psychological components of quality of life (QOL). Data were using multiple regression and a simple mediation model applying the PROCESS macro for mediation. Result(s): Physical functioning explained 14.5% of variance in cognitive functioning. Physical and cognitive functioning together explained 22.4% of variance in physical component of QOL, 18.7% of variance in mental component of QOL. Indicators of physical functioning significantly related with cognitive functioning with balance (B=0.41, p=.02). Cognitive functioning had significant indirect effects B= 0.19, 95%CI (.491~.008) between balance and physical component of QOL, while the indirect effects was not significant with mental component of QOL (B=0.06, 95%CI -.107~0.332). Conclusion(s): The findings showed cognitive functioning had a significant mediating effects between the physical functioning and physical components of QOL. These findings have suggested that nursing intervention to improve physical functioning such as balance, mobility and grip strength may also improve cognitive functioning, consequently improving physical component of QOL for older adults with mild cognitive impairment. Further studies are warranted to explore the effects of health promotion programs designed to enhance physical and cognitive functioning in this population.