This study investigated the relationship between a trauma-related stressor and smoking withdrawal symptoms in 25 male Vietnam combat veterans with posttraumatic stress disorder (PTSD) using a within-subjects design. All subjects were smokers. The stressor involved a modified Stroop task, in which the veterans color-named either anxiety-related or neutral control words. Anxiety-related words produced more withdrawal symptoms than neutral control words, including increased craving, negative affect symptoms, somatic symptoms, and lack of alertness.