KORea ECOlogical Risk assessment (KORECORisk) was developed to support decision making for the ecological risk-based management of chemicals in industrial complexes in South Korea. The system is based on a geographical information system and consists of a release rate estimation module, an exposure estimation module, and an ecological risk assessment module. For release rate and exposure estimation, the chemical use data from the national chemical inventory database and a dynamic multimedia fate model, respectively, were used. The ecological risk was assessed by calculating the risk quotient. A case study was presented to demonstrate an application of KORECORisk to setting a risk-based priority among the 6 major industrial complexes or among the chemicals used in the individual industrial complexes. Furthermore, a more detailed assessment was performed to demonstrate and evaluate a potential use of KORECORisk for the management of individual complexes. With 3 phthalates (1,2-benzenedicarboxylic acid dibutyl ester; 1,2-benzenedicarboxylic acid dimethyl ester; and 1,2-dibenzenedicarboxylic acid dioctyl ester) as model chemicals, KORECORisk provided prediction in time and space that are of sufficient resolution required for the aquatic risk assessment but with varying uncertainty. The uncertainty associated with the use of KORECORisk appeared to vary widely (from <10 to 10³) with the chemical. Within the range of the chemicals tested, the release rate estimation appeared to introduce larger uncertainty than the exposure estimation. A more accurate chemical use inventory would improve the accuracy of not only the chemical release estimation but the exposure estimation module by reducing the influence of the unidentified sources. The release estimation module should be modified to provide temporal variation with a time resolution relevant to the exposure duration for which toxic effects could occur.