Global climate change is expected to affect future storm characteristics. The change should properly be taken into account when assessing future flooding risks in urban areas. This study presents a method for quantifying the increase in flood risk caused by global climate change in the framework of urban flood risk management. Flood risk in this context is defined as the product of flood damage ... [Show full abstract] potential and the probability of its occurrence. The study utilizes a geographic information system (GIS) based flood damage prediction model (FDPM) to calculate the flood inundation damage caused by design storms with different return periods. Estimation of the monetary damages by these storms and their return periods are forerunners to flood risk calculations. The design storms are developed from modified intensity-duration-frequency (IDF) relationships generated by simulations of global climate change scenarios (e.g. CGCM2A2).The risk assessment method is applied to the Kanda River basin in Tokyo, Japan. The assessment provides insights not only into the flood risk cost increase due to global warming, and the impact that increase may have on flood control infrastructure planning.