Comparison of fluvial successions in river valleys dating from marine isotope (MI) Stages 4 and 3 in a west-east transect from Britain to Poland shows the spatial and temporal variation in palaeohydrological characteristics of northwest European river valleys during these stages. MI Stage 4 has been a period of deep fluvial incision. Following this erosion, most valleys were filled during MI Stage 3 with successions of gravelly river deposits (Britain) or sand/silt/peat successions (northwest European lowlands). The sedimentology of the deposits suggests strong discharge variations, caused by a nival discharge regime with pronounced spring snowmelt discharges. The MI Stage 3 climate oscillations generally cannot be traced in the fluvial record. An incision phase of Hengelo interstadial age has been found in the Netherlands, but similar incision phases related to other warming events have not been proved convincingly. The restricted reaction of the river systems is caused by the absence of geomorphologically effective vegetation changes and relatively minor variations in precipitation during MI Stage 3. Over longer time scales, silt and peat beds gradually decrease in the younger (post-Hengelo/Upton Warren) part of MI Stage 3, corresponding with evidence of aeolian activity and permafrost. This is related to the longer duration of the stadials in this part of MI Stage 3. © 2001 Elsevier Science Ltd and INQUA. All rights reserved.