The migration and delivery of filter flavour agents were studied by dissolving 10 model flavour compounds in triacetin at 10 mg/ml each and fabricating cigarettes with flavoured filter tips. The concentrations of these compounds in filters, tobacco, and smoke particulates collected on Cambridge filters were determined by capillary column gas chromatography initially and after 1, 2, 4, 6, and 8 weeks. Flavour migration was found to obey first-order kinetics, with the rate constant being determined by the volatility of the flavour compound dissolved in the plasticized filter. Delivery of flavour compounds decreased with time at a greater rate than could be explained by flavour migration. A high correlation between the solubility characteristics of the flavour and its rate of delivery efficiency loss lead to the proposed explanation that flavour compounds diffuse into the cellulose acetate fibers with time and become less accessible for elution into the smoke aerosol. Model compounds with poor solubilities in plasticized cellulose acetate remain near the surface of the fibers where they are readily eluted into the mainstream smoke and, consequently, exhibit smaller delivery efficiency losses with time. Ventilation was observed to initially increase the ratio of flavour to TPM delivery, but this advantage was lost as the cigarette aged.