The Quaternary evolution of Cotentin, (Normandy, France) is documented through two types of investigations: geomorphology and sedimentology. The Cotentin geomorphic system is divided into three plateaux gently dipping towards the coast. Quantitative morphometry of drainage network indicates landform rejuvenation and uplift of the South Cotentin area. Fault scarps are recognized between the three topographic zones. They coincide with seismic lineaments and generate knickpoints along thalweg profiles or modify the sinuosity of the lower part of the alluvial channel. The evolution of western Normandy during Pleistocene time is presented. The early Pleistocene environment is initially marine and cold. The environment then becomes fluviatile with a tectonic control on continental sedimentation. Finally, floodplain silts and peats were deposited in an anastomosed river system which persists actually.