Shifting cultivation patches distributed in the Kotopanjang dam watershed in central Sumatra were detected by the analysis of 4 datasets of Landsat imagery acquired in 1985, 1989, 1992 and 1994. Detection of shifting cultivation areas was performed based on sifting using patch size and the normalized difference vegetation index (NDVI) from bare lands obtained by unsupervised clustering and maximum likelihood classification. Area, name of subwatershed, location of center, average elevation, average slope gradient and the NDVI values were computed for each detected patch and registered in a database. Overlaying of results revealed an increase of shifting cultivation patches in this area year by year. Furthermore, it appeared that the increase of the number of patches occurred in specific areas such as surroundings of villages and newly developed areas after dam construction. Sub-watersheds in which much attention should be paid to land degradation were identified by assessing and temporal characteristics of shifting cultivation patches.