Information on the spatial distribution of different wasteland categories forms a basic component in the large-scale reclamation and utilization programmes of these degraded lands. To evaluate the use of Landsat Thematic Mapper (TM) data in wasteland mapping, an attempt was made in this study to delineate and map various kinds of wastelands, in parts of Aligarh District (Uttar Pradesh) by digital analysis of Landsat TM data of 27 January 1986, using the maximum-likelihood classifier method. Map-to-image rectification of the sub-image and a selection of suitable spectral bands based on spectral response and training statistics, were also performed before the final supervised classification. The results indicated that, out of the six TM bands (excluding the thermal band), the spectral separability of all wasteland categories are most possible in bands 3, 4, 5and 7. This study also reveals that wasteland types, namely salt-affected and surface waterlogged/marshy lands could be effectively delineated, mapped and digitally classified with an accuracy of about 96 per cent, using spatially and spectrally improved Landsat TM data.