Purpose: The purpose of this study was to identify the relationship between physical activity and sleep patterns of the elderly. Methods: The subjects of this study were 154 elderly who visited a community senior center in Korea. Data was collected by an interview and a self reported questionnaire, during the period from June to October, 2006. Physical activity was measured by IPAQ Korean version(2006), and sleep pattern by Korean Sleep Scale A developed by Oh et al.(1998). Results: The prevalence of chronic illness in the subjects was 73.4 %. The mean time of vigorous activity was $6.62{pm}31.27$ minutes/day during the past week. Moderate activity time was $28.85{pm}50.31$ minutes/day and walking time was $28.85{pm}50.3$ minutes/day. The total sleep time was $397.63{pm}111.53$ minutes/day. Physical activity of the elderly significantly correlated with sex, chronic illness, job, and sleep patterns of the elderly. Stepwise multiple regression analysis revealed that the most powerful predictor of sleep pattern was the satisfaction of sleep. A combination of the number of chronic illnesses, moderate physical activities(MET), and total time of sleep accounted for 44.4% of the sleep pattern. Conclusions: Moderate physical activity is more effective than vigorous physical activity for improving the sleep quality of the elderly.