This paper compares the different geomorphological processes occuring during Pliocene-Quaternary times on two very similar slopes in Mallorca, one located in the Tramuntana Range and the other in the Llevant Ranges. Both slopes have the same geological structure and lithological and stratigraphical levels, the same altitude, orientation, vegetation and average temperature and precipitation. The different slope processes are caused by the relationship between accommodation rate and the sedimentation rate in the adjacent basins. This relationship is bigger at the basin associated to the Tramuntana Range and give rise to major landslides on the Tramuntana slope, whereas the Llevant Ranges slope is dominated by the presence of alluvial fans and debris screes