A series of papers have been presented at previous conferences examining the characteristics of filter cigarettes containing activated carbons. All these studies related to standard circumference cigarettes, but comparatively little is known about the performance of superslim carbon filters. Superslim products are one of the most rapidly growing segments of the cigarette market and so the purpose of this work was to explore the performance of carbon filters when used in superslim products. Their lower circumference means that the smoke velocities passing through the filter are approximately double those of standard products, resulting in shorter contact times. Smoke velocity is an important parameter governing the performance of filters in terms of both particulate retention and vapour adsorption. This paper examines the extent to which the efficiency of carbon is affected when used in superslim filters. Experimental findings are presented of the relative retentions by non-ventilated filters containing coconut-based carbons of twelve vapour phase compounds - notably carbonyle and hydrocarbons - under both ISO and Canadian Intense smoking regimes. Filters containing carbons of two different activities were tested over a range of carbon weights using a methodology similar to that described at previous TSRC conferences. Conclusions will be drawn concerning the interaction between these various factors and comparisons will also be made with the results from standard circumference products.