Several studies have linked posttraumatic stress disorder with heavy smoking. It is not known to what extent this association is specific, as opposed to being a function of a joint association of PTSD and heavy smoking with a third variable such as depression proneness. In a cross-sectional study of 157 current regular smokers, severity of nicotine dependence (but not cigarettes smoked per day) was positively correlated with total PTSD symptoms, hyperarousal symptoms, and avoidance symptoms. These correlations were not eliminated by controlling statistically for depression vulnerability, whether it was measured on a continuous self-rating scale or on the basis of interview-diagnosed history of major depression. The association between PTSD and nicotine dependence was stronger among men than among women.