Calculations of pressure and production histories are presented for one‐dimensional flow of non‐ideal gases through porous media. The non‐ideal properties considered in this paper are the gas viscosity and deviation factor (compressibility factor) which are assumed to vary as simple functions of pressure. The effect of each of these parameters is investigated independently as well as in combination. The results demonstrate that pressure declines and production histories in linear gas‐flow systems are markedly influenced by variations in these parameters. Numerical solutions of the flow equations were obtained by solving the corresponding difference equations on an electronic digital computer.