Significant overpressures are either controlled mechanically by the fracture pressure or by the matrix permeability if there is no leakage on fractures. In a recent publication in this journal Nysæther (2006) attempts to explain the degree of overpressure in reservoirs from Haltenbanken based on a pressure cell model. The paper contains interesting data and discussions, but his model is based on much too simplistic assumptions about fluid flow in sedimentary basins.