Using observational data acquired during the Monsoon Trough Boundary Layer Experiment (MONTBLEX-90), the drag coefficient CD is estimated over two land stations, Jodhpur (arid region) and Kharagpur (moist region), by eddy correlation of velocity data from sonic anemometers. At low winds CD varies with wind speed according to a power law, which at Jodhpur takes the form CD=0.04 U¿-1.0610 (U¿10 being the mean wind speed at 10 m). The large values of the drag coefficient at low winds are associated with both near-neutral and strongly unstable situations. On the other hand the CD values at Kharagpur are less than at Jodhpur by nearly 50% for wind speeds >3 ms-1 and cannot be explained by the different roughness lengths at the two sites. ¿ American Geophysical Union 1996