This study employed secondary analyses of existing ecological momentary assessment (EMA) data to characterize hostile and irritable affect in the day-to-day experience of 52 smokers with, and 65 smokers without, posttraumatic stress disorder (PTSD). EMA monitoring occurred over a mean of 8.2 days, and participants responded to an average of 2.8 random prompts/day. Analyses included Wilcoxon rank sum tests of group differences, and path analyses of cross-lagged multilevel models. Participants with PTSD endorsed a significantly higher proportion of total EMA entries indicating hostile affect and irritable affect than did individuals without PTSD. Cross-lagged analyses indicated that over a period of hours, PTSD symptoms significantly predicted subsequent hostile and irritable affect, but hostile and irritable affect did not predict subsequent PTSD symptoms. Findings suggest that day-to-day exposure to PTSD-related trauma cues may contribute to chronically elevated levels of anger-related affect. Such heightened affective arousal may, in turn, underlie an increased risk for verbal or physical aggression, as well as other health and quality-of-life related impairments associated with PTSD. Clinical implications include conceptualizing anger treatment in the broader context of trauma history and symptoms, and specifically targeting physiological arousal and maladaptive hostile cognitions triggered by trauma reminders in patients with PTSD.