Asia's coastal megacities are increasingly vulnerable to flooding disasters resulting from the combined effects of climate change (manifested as sea level rise, intensified storms, and storm surges), land subsidence, and rapid urban growth. Development of risk-management strategies, such as improved infrastructure, early warning systems and evacuation plans, and disaster response and relief aid, is urgently needed in all these cities. But substantial barriers to implementing these measures must first be overcome: lack of awareness, the distracting immediacy of other problems, budgetary constraints, and governance issues. Despite the absence of precise climate change predictions, recent studies suggest that climate change, sea level rise, and sinking deltas are occurring at much faster rates than were projected only a few years ago. Implementation of climate risk management in planning and policy must be given high priority if there is hope of meeting the twin challenges posed by climate change and urban growth.