Abstract By using the cell model as a statistical mechanical basis and the atom-atom potential scheme as an approximation to intermolecular potential, the thermodynamic properties of the pyrene and naphthalene crystale are calculated at some temperatures between 100 and 300 K. The partition functions of the crystals are computed by the importance sampling (Monte Carlo) method. The literature and own experimental data on thermal expansion are used. The calculated thermodynamic functions show good agreement with experiment. For some temperatured the calculation results are compared with those obtained in the quasiharmonic approximation.