Changes over time in posttraumatic stress disorder (PTSD) symptoms during periods when individuals with substance use disorders remain abstinent has not received much attention. PTSD symptomatology over a 36-month period was studied in cocaine-dependent individuals (N = 34) who entered a pharmacologic trial targeting cocaine use and depression, but did not include any treatment for PTSD. All participants reported at least one PTSD Criterion A event, and 17.6% had current PTSD at baseline (Base PTSD+). Significant improvements in PTSD symptoms were observed on global measures of PTSD, but not on the Impact of Events Intrusion subscale. Significant improvement in drug use severity also was observed. Compared with participants who were negative for PTSD at baseline, Base PTSD+ participants were significantly more likely to: (a) meet criteria for current PTSD at follow-up and (b) have been re-victimized over the time period of the study. Careful evaluation of intrusive symptoms may be particularly important when diagnosing PTSD in individuals with SUDs, and repeated assessment of traumatic experiences may be necessary in longitudinal studies.