Modeling flood inundation has become increasingly significant, especially for urban setting. Information on flood characteristics and accurate flow paths is significant for storm water management, hydrological modeling, hydrological data analysis, and vulnerability assessment. This paper employed geographic information system (GIS) to process the input data, RIDF curve to generate different design storm scenarios and PCSWMM to simulate the urban flooding of the Luinab catchment in Iligan City, Philippines. The results demonstrate the methodology for integrating GIS and flood model for analyzing the hydrological behavior of the catchment. The calibrated model clearly identified the area prone to flooding and predicts the influence of imperviousness on the hydrological behavior of the catchment. Improvement of the drainage system could be achieved by a) increasing the capacity of main canal and/or b) providing an additional outlet from identified areas that are prone to flooding.