This chart review examined the effects of a six-session cognitive-behavioral therapy for insomnia (CBT-I) group in a sample of veterans diagnosed with posttraumatic stress disorder (PTSD) receiving residential PTSD treatment. Earliest-session scores on self-report sleep variables were compared to final-session scores among the 47 veterans who received at least five group sessions. Separate analyses were performed for the 39 veterans for whom the PTSD Checklist (PCL-M) scores before and after CBT-I were available, with change in the PCL-M score (10-point decrease or not) as a factor. Repeated-measures analyses of variance indicated significant improvements in the time awake after sleep onset, F(1, 46) = 4.17, p < .05; time in bed, F(1, 46) = 4.06, p < .05; sleep efficiency, F(1, 46) = 4.71, p < .05; and Insomnia Severity Index score, F(1, 46) = 38.8, p < .001. There were no significant effects for sleep onset latency or total sleep time. For veterans with available PCL-M scores, there were no significant interactions between PTSD score change and any of the sleep variables analyzed. These results add to the literature indicating that CBT-I is an effective treatment for insomnia with veterans diagnosed with PTSD. The suitability of CBT-I in residential treatment settings is also discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved)