Abstract Two long refraction lines parallel with the structural strike show that the Moho of the subducting oceanic Arabian plate dips north beneath the Makran accretionary prism at an angle of less than 2°. The downgoing plate carries a thickness of about 7 km of sediment into the accretionary wedge. The accreted sediment rapidly consolidates with a concommitant increase in seismic velocity. Slope sediments are trapped in narrow, well-lineated slope basins formed between uplifted fold ridges, and the dip of sediment layers within these slope basins records the progressive tilting of the margin towards the coast. We document the shapes of channels along which downslope sediment movement occurs. Decoupling layers within the sediments, caused by high pore pressures generated by the non-expulsion of pore water from overpressured shale sections, control the deformation in the frontal 70 km of the accretionary prism.