Test strips impregnated with phenylthiocarbamide (PTC) have been used to identify genetic differences based on whether a bitter taste is perceived. To determine whether smokers who perceive PTC as bitter tasting ("tasters") would differ from those who describe it as tasteless ("non-tasters") on smoking-related variables, we studied 464 current smokers (70% female, 79% White; mean age 30.5 +/- 9 years) recruited to participate in laboratory experiments and clinical trials. Of these, 217 (47%) reported the PTC strips as tasteless and 154 (33%) as tasting bitter. The remaining 93 (20%) described the taste as salty, sweet, or other and were excluded from further analyses. Comparing tasters with non-tasters, we found significant differences in mean (S.D.) total years smoked (14.5 [9.2] for non-tasters, vs. 12.6 [8.4] for tasters, p <.05), Fagerstrom Tolerance Questionnaire scores (6.4 [2.1] vs. 5.8 [2.1], p <.01), and scores on the Positive Reinforcement scale of the Michigan-Nicotine Reinforcement Questionnaire (8.1 [2.9] vs. 6.8 [3.1], p <.05). Results suggest that among smokers, ability to taste PTC may confer some protection from development of nicotine dependence and positive reinforcement from smoking. (c) 2006 Elsevier Ltd. All rights reserved.