This study investigated the association among cigarette smoking, posttraumatic stress disorder (PTSD), and ambulatory cardiovascular and mood monitoring in 117 male Vietnam combat veterans (61 with PTSD and 56 without PTSD). Positive smoking status was associated with higher systolic blood pressure (SBP) and heart rate (HR), as well as greater diastolic blood pressure (DBP) variability. Compared to individuals without PTSD, PTSD patients had higher HR, anger/hostility ratings, and depression/anxiety ratings. Significant diagnosis by smoking status interactions were found indicating that compared to nonsmokers with PTSD, smokers with PTSD had higher DBP, mean arterial pressure (MAP), and positive affect. Ad lib cigarette smoking during the previous 30 min did not have a significant effect on mood or cardiovascular parameters, except in non-PTSD smokers who reported lower depression/anxiety ratings after smoking. Findings suggest that the effect of smoking on cardiovascular parameters may be amplified in smokers in PTSD. Findings suggest that the interrelationships among cardiovascular parameters, cigarette smoking, and PTSD deserve more research attention.