A case-control study of lung cancer involving interviews with 7,804 cases and 15,207 hospital-based controls was carried out in seven locations in Western Europe. The large study size permitted the calculation of precise estimates of the relative risk of lung cancer associated with smoking different types of cigarettes. Lifelong nonfilter smokers were at nearly twice the risk of lung cancer compared to lifelong filter smokers after controlling for duration of cigarette use and number smoked per day (RR = 1.7 for males and 2.0 for females). Lung cancer risks for filter, nonfilter and mixed smokers increased in proportion to intensity and duration of smoking and decreased with years since stopping smoking. The findings indicate that prevention activities should continue to emphasize smoking cessation, although switching to low-tar cigarettes may also yield some reductions in lung cancer risk.