In this work we describe the role of landslide processes in shaping river channels and the development of valley floors in 3^rd and 4^th order catchments in the Polish Flysch Carpathians. The main focus of the study was on the contact zone between the landslide system and the river channel, where it has been shown that 30.2% of the length of the river network are affected by landslides. Research shows that 93% of landslides have some form of contact with the river system. Research further shows that the most common contact types in the study are point and area types according to the Korup classification. The most common impacts of landslides on the river channel are riparian and partial occlusion types. Landslides very often cause complete or partial displacement of the river channel, which frequently leads to the blockage of flow, which in turn creates landslide lakes, followed by accumulation zones. The effect of such events is the transformation of the longitudinal profile of the river and the intensification of erosive processes in the contact zone and downstream. Increased activity of erosive processes can lead to the activation of landslide processes, including on the opposite slope.