In this paper, the potential of using passive microwave observations to detect and monitor flood was explored during the time period 2005–2009. Data from the Advanced Microwave Scanning Radiometer (AMSR-E) was used to evaluate the performance of radiometry in flood monitoring and detection. The current study demonstrates the potential of these observations to monitor the floods in the Sundarban Delta (India / Bangladesh). There is a clear effect expressed by low brightness temperature and high polarization index (i.e. higher soil moistures) over the affected areas after floods or heavy rainfalls. The use of remotely sensed passive microwave observations can improve the forecasting skill of flooding at regional scale.