A one-dimensional mathematical model to predict filter rod ventilation and pressure drop has been developed. The model consists of Darcy air flow inside the filter rod and air flow through the combination of perforated tipping paper and porous plug wrap paper bearing a non-linear relationship with respect to pressure difference across both the papers. Since a lateral flow occurs between the tipping and plug wrap papers, it has been assumed that the dilution air flows into the filter through a ring-shaped effective area with a certain width around the plug paper. This ring is situated directly below the perforation rows. Such flow pressure relationships were expressed in a set of simultaneous first-order ordinary differential equations. This filter rod ventilation model was combined with the tobacco rod ventilation model in series and solved using the Runge-Kutta-Gill method under a given set of boundary conditions and physical parameters. Laser perforated tipping and porous plug wrap papers of differing air permeability were prepared for the experiments. The width of the effective area was determined experimentally. Calculated filter rod ventilation, tobacco rod ventilation and pressure drop were compared with experimental results under a constant drawn flow rate and an intermittently drawn flow with a sinusoid-shaped puff profile. The calculated results were in fair agreement with experimental indicating that the proposed model should be valid and useful for the estimation of the tobacco and filter rod ventilations.