Additives used in tobacco product manufacturing are currently in the focus of public discussions with regard to potentially increased consumer health risks on account of certain additives. In addition, a few additives are suspected to enhance the addictiveness of tobacco products. In 2006, the German Federal Ministry for Food, Agriculture and Consumer Protection (BundesministeriumfuerErnaehrung, Landwirtschaft und Verbraucherschutz, BMELV) commissioned a research project intended to provide support for the evaluation of additives and their influence on the composition and properties of cigarette mainstream smoke. In this paper the results of the study are reported. Different amounts of glycerol, cocoa powder and sucrose were added to the tobacco of two kinds of filter-ventilated King size test cigarettes with ‘tar’ levels of 6 mg and 10 mg per cigarette. The tobacco of the test cigarettes consisted of a commercially available blend made of Virginia, Burley and Oriental tobaccos. Machine smoking was performed according to the applicable ISO smoking regimen. Various smoke components, which are suspected to be harmful for health, were determined in mainstream smoke. Increasing levels of sucrose were correlated with an increase of the amount of formaldehyde but not of acetaldehyde in the mainstream smoke of the test cigarettes. In cigarettes with different levels of added glycerol no substantial change in smoke composition was observed. The addition of cocoa powder to tobacco resulted in a decrease of tobaccospecific N-nitrosamines in mainstream smoke. The results obtained in this study can be used as evidence for the toxicological evaluation aimed at approving or banning specific additives for tobacco product manufacturing.