Polypharmacy is prevalent among the aging population and has been a public health concern worldwide. Polypharmacy can have various negative effects on health, thus increasing the healthcare costs among the elderly. This study aimed to identify the prevalence and risk factors of polypharmacy among community-dwelling elderly in South Korea using nationally representative sample data. This cross-sectional, descriptive study used data from the 4th wave of the Living Condition of Elderly Study in South Korea conducted in 2017. The data of 12,290 participants aged ≥65 years were analyzed. Polypharmacy was defined as the use of five or more prescribed or non-prescribed medications for over 3 months. The prevalence of polypharmacy was 39.3%. The elderly showing a significant correlation with polypharmacy were predominantly women, older in age, less educated, and not married. Multivariate logistic regression analysis showed that the greatest risk factor of polypharmacy was presence of angina or myocardial infarction (OR = 5.506, 95% CI = 4.528, 6.695, p < .001). The other risk factors included advanced age, a lower level of education, diagnoses of stroke, hyperlipidemia, hypertension, diabetes, low back pain, and depression. This study found that the prevalence of polypharmacy in community-dwelling older adults in South Korea was high. When controlled for other variables, advanced age, a lower education level, cardiovascular diseases, low back pain, and depression were found to be independent risk factors of polypharmacy. Further studies need to be conducted regarding changes in the prevalence of polypharmacy over time and its relationships with different variables in the long term.