Algerian soil is exposed to intense soil erosion due to several factors, mainly natural and human. In the present work, the assessment of soil erosion-deposition processes in a forest area using the fallout radionuclide cesium-137 is proposed. The Cs-137 technique, which is used for investigating rates and patterns of soil erosion, has been successfully applied in a wide range of environments. This radionuclide is known to strongly adhere to soil particles and therefore can be used as a tracer in soil movement investigations. Three different sites were selected for this study, namely a forest site, a burnt forest site and an agricultural one, all located in a Mediterranean area near Tenes (North-Central Algeria). The results showed that the agricultural site is characterized by the highest decrease in cesium-137 activity and is then the most exposed to soil erosion. Cesium-137 activity in the reference site is about 2842 Bq center dot m(-2). It varies from 2288 to 4464 Bq center dot m(-2) in the burnt site, from 1951 to 3440 Bq center dot m(-2) in the forest site, and from 1359 to 2448 Bq center dot m(-2) in the agricultural site. Results showed that the erosion rate reaches a maximum value of 39 t center dot ha(-1)center dot yr(-1) in the agricultural site, 9.92 t center dot ha(-1)center dot yr(-1) in the forest site, and 5.63 t center dot ha(-1)center dot yr(-1) in the burnt site, whereas the highest deposition rate is about similar to 16 t center dot ha(-1)center dot yr(-1) both in the burnt site and in the forest site. Such results contribute to a better understanding of land degradation processes and are of great assistance to rural engineers and local authorities in charge of the implementation of soil conservation measures, especially in such a semi-arid environment where combating desertification is a crucial issue.