The present work examines mathematical modeling and simulation of drying and pyrolysis of porous media. The equation system presented is basic for modeling of heat and mass transfer in porous media when drying and pyrolysis appear. The set of differential and algebraic equations is discretized in space by first-order upwinding and central differencing, and is integrated in time by the differential/algebraic equation solver named DASSL. The developed program system is tested by simulating drying and pyrolysis of wood, and hence necessary submodels for the transport and physical properties of wood are given. The simulations are done for one-dimensional transient problems in Cartesian coordinates. Two examples are shown, one with pure drying at moderate temperature and one with combined drying and pyrolysis at high temperature.