Accelerated soil erosion and land degradation represent major environmental problems for agricultural lands. Reliable information on the rates of soil loss is urgently needed. The traditional techniques for documenting rates of soil loss may meet this need, but face many limitations. The fallout radionuclides, especially 137Cs and 210Pbex, are increasingly used as effective tracers to quantify soil erosion rates, and they represent a valuable complement to the existing classical methods. This paper aims to introduce the basis for assessing soil erosion rates on cultivated and uncultivated slopes by using 137Cs and 210Pbex measurements, to compare the 137Cs and 210Pbex reference inventories, and to report several case studies undertaken in the hilly area of Sichuan Basin and the Three Gorges area of China.