The fallout radionuclide cesium-137 (Cs-137) has been widely employed as a tracer for assessment of soil loss from thick uniform soils; however, few studies have been conducted on thin stony soils on slopes underlain by carbonate rocks which are widely distributed in karst areas.  Information derived from Cs-137 measurement of soil samples collected along a carbonate rock slope with thin stony soil where neither soil erosion nor deposition occurred was used to investigate the characteristics of Cs-137 redistribution in a karst area of Southwest China.  The results indicated that the Cs-137 inventories of the surface soil on the slope studied were much lower than that of the local Cs-137 reference inventory and the Cs-137 activities were much higher than those on slopes with thick uniform soils.  The spatial distribution of Cs-137 inventories was characterized by considerable variation.  The high Cs-137 depletion in the stony soil of the slope studied was mainly because a considerable proportion of the fallout input of Cs-137 could be lost with runoff and the dissolution of carbonate particles in the soil promoted the loss of Cs-137.  These demonstrated that the rates of soil loss could not be estimated from the degree of depletion of the Cs-137 inventory relative to the local reference inventory for the thin stony soil of the rocky slope underlain by carbonate rocks in the study area in the way that has been widely used in areas with thick uniform soils.