PURPOSE: The purpose of this study was to project supply and demand for registered nurses to the year 2015 and to make recommendations regarding nurse manpower planning for the 21st century in Korea. METHODS: The supply of nurses was predicted using a baseline projection and demographic methods. The demand for nurses was forecasted by the derivative method. RESULTS: Projections indicate there will be an oversupply of nurses based on the current productivity. However, there will be under-supply if predictions are based on the standard for nursing staff established by the medical law and the optimal productivity derived by the patient classification system. CONCLUSION: Korea needs more practicing nurses. One way to increase the number of practicing nurses is to increase the number of graduates. However, considering the low retention rate of nurses, a better way to solve the nurse shortage problem is to develop strategies to recruit and retain nurses.