The continuing trend to lower cigarette yields and to modify cigarette taste have lead to an increasing use of ventilation and granular adsorbent additives in cigarette filters. In a non-ventilated cigarette, smoke is generally fairly evenly distributed throughout the filter. The"coring"or uneven distribution of smoke downstream of the ventilation holes in a ventilated cigarette filter is well known. However, very little work seems to have been carried out on the effect of such uneven smoke distribution on the activity of granular adsorbents in the filter of a ventilated cigarette. To investigate any possible effect, the vapour phase retention of a number of filters containing carbon at different ventilation levels has been studied. The cigarettes were smoked on an SM302 smoking machine adapted to conform to the latest CORESTA/ISO (harmonised) standards. The vapour phase was collected for subsequent analysis by high resolution capillary gas chromatography. The filters were chosen such that the carbon was : a) evenly distributed throughout the active segment, b) located on the circumference of the active segment and c) located in the core of the active segment. In all cases tests were carried out with the active segment both upstream and downstream of the ventilation holes. The vapour phase removal efficiency factors calculated at each ventilation level will be presented demonstrating the effect of carbon location and ventilation on activity.