An accurate characterization of soils and good knowledge of the soil physicochemical properties is the key to understanding ¹³⁷Cs data and assesses the effect of soil type and different land uses on the behavior of the radionuclide ¹³⁷Cs in the soils. In this research, representative soils of mountainous Mediterranean agroecosystems have been characterized through the study of soil pits, a detailed determination of physicochemical soil properties and the analysis by X-ray diffraction of soil profiles. Furthermore, to assess the impact of land use on the content and distribution of ¹³⁷Cs, its implications on the soil loss processes, and the ¹³⁷Cs transfer to plants, 13 sectioned soil profiles in agricultural and forestry soils, in Calcisols, Leptosols, Regosols, Gypsisols and Gleysols, have been sampled. The physicochemical soil properties varied widely and also the content of ¹³⁷Cs, which was significantly positively correlated with organic matter. The highest values of ¹³⁷Cs were found in uncultivated Leptosols under forest soils, with the highest concentration in the topsoil and a sharp decay with depth, while the lowest values of ¹³⁷Cs were found in cultivated Gypsisols and Regosols, in which the radionuclide was distributed homogeneously throughout the soil profile by tillage effect. Information gained with this research demonstrated the effect of soil type and land use in the content of 137Cs on the soil, and is of interest for the correct application of the ¹³⁷Cs technique to quantify soil loss in Mediterranean agroecosystems