In this paper, the Hydrologic Data Management System (HDMS) was developed for the efficient management of hydrologic data. The applicability of the system was demonstrated using the hydrologic data of study watershed located in the southwest from Suwon city MySQL 5.0, relational database management system, and MS Visual Basic 6.0 were used for the development of MS windows based HDMS. The primary components of the HDMS are data search system, data management system, and data analysis system. Data search and management systems provide basic functions for the efficient data search, storage, update and export. Data analysis system enables the users to get the further and diverse hydrologic statistical information from the stored data. Furthermore, the accuracy and quality of hydrologic data was analyzed and evaluated through data analysis system.