ABSTRACT: BACKGROUND: In Sweden NRT-products and Snus, are easily available and used as smoking cessation aids. However, most quit attempts are made without any cessation aids. The limited use of these products as cessation aids may be influenced by the way smokers perceive the harmfulness of NRT-products and Snus compared to smoking. The present study examines these perceptions and their association with perceptions of the harmfulness of nicotine itself. METHODS: The study is based on the Swedish part of a two-nation web-based survey of daily smokers in Sweden (n=1016) and Norway (n=1000). Questionnaire items addressed perceptions of NRT-products' and Snus' harmfulness and nicotine's part of the health risks of smoking. Data analyses included cross-tabulations and logistic regressions. RESULTS: A majority, 59 % of the answers to the question about harmfulness of NRT-products, and 75% of the answers about harmfulness of Snus, were inconsistent with the scientific evidence by demonstrating exaggerated perceptions of harmfulness. The strongest predictor of consistent answers was the perception of the harmfulness of nicotine. There were also significant associations with own experience of successful use of the products in question. Overall the perceptions of the harmfulness of nicotine were considerably exaggerated. This pattern was more pronounced among women than men. Prevailing misperceptions may be related to the way that different tobacco and nicotine products are presented in the media and other publicly available information sources. CONCLUSIONS: Public information about smoking and health should be expanded to include objective and unambiguous information regarding nicotine's part in the harmfulness of smoking and the harmfulness of different nicotine-containing products compared to smoking. This is essential in order to preclude that misperceptions regarding these matters could discourage smokers from adopting effective cessation practices with use of nicotinecontaining aids.