In the current study, the revised universal equation of soil losses (RUSLE) is implemented, to assess the risk of water erosion in the Sebou watershed (Morocco). The calculation of erosion requires a huge amount of information and data from various sources available in different formats and scales. Therefore a geographic information system (ArcGIS 10.2) was used, which allowed ease and considerable time savings in the organization and processing of spatial data showing the effects of each factor affecting soil erosion. This erosion is influenced by topography, rainfall, soil properties, the conditions of crop management, and finally conservation practices. The average annual soil loss was calculated by multiplying these five factors. The results show that 78.83 % of the study area has a low risk of erosion, 17.36 % medium risk, 3.04 % high risk and 0.77 % a very high risk.