Cigarette smoke is a complex mixture containing various toxic species which constitute a serious health risk in the vapour phases. Compared to the other adsorbents, porous carbons are considered as the most effective and convenient sorbents for removal of vapour phase toxicants in cigarette smoke owing to its unique physical and chemical properties. However, the effect of tar deposition on the performance of porous carbons is poorly understood. The objective of this study is to investigate the contribution of tar deposition to decreasing carbon activity in a cigarette filter and subsequently what the important carbon variables are to minimize this. Also we aim to establish the relative constructions towards porous carbon deactivation from the smoke particulate phase and the smoke vapour phase and what carbon parameters give the greatest adsorption in the cigarette filter and what types of compounds are adsorbed.A series of porous carbons with different pore structure and surface chemistry were used as adsorbents. Cambridge filter pads were used to remove the tar in the cigarette smoke. In order to obtain different degrees of tar deposition, the location and number of Cambridge filter pads in a cigarette filter were varied.Tar deposition has a complex effect on the adsorption ability of the porous carbon. In general, porous carbon protected with a small Cambridge pad reduced the tar deposition on the carbon resulting in a greater adsorption capability for vapour phase smoke toxicants. Using commercial coconut carbon, the deposition of tar on the surface hindered the adsorption of the majority of vapour phase smoke toxicants measured. Further studies using other porous carbons resulted in a similar conclusion.