Being highly dynamic by nature due to their changing hydrological regime and to the encroachment of urbanization, inductrialization and changing patterns in agriculture, reliable and timely information about the extent, nature, spatial distribution and temporal behaviour of wetlands is a prerequisite for their effective management. Optical remote sensing data have been used extensively to generate such information. In this study the European Remote Sensing (ERS-1) Synthetic Aperture Radar (SAR) data collected during April 1993 were used to study the temporal behaviour of the coastal wetlands of the Sunderban delta of West Bengal, India. Account was also taken of the Landsat MSS data of 1973. Shrinkage in the wetlands on the periphery of Calcutta due to the encroachment of urbanization and the development of new islands in the active coastal zone have been observed over a period of 20 years.