Current efforts to disseminate evidence-based psychotherapies (EBPs) for posttraumatic stress disorder (PTSD) in Veterans Affairs Medical Centers (VAMCs) have made effective treatment options more available throughout the system. Yet many veterans identified as likely to benefit from such services choose not to utilize them. The evidence base regarding factors that contribute to treatment initiation among those offered EBPs is still in its early stages. The present study investigated clinical presentation, patient demographics, and environment of care factors as potential predictors of EBP treatment initiation among veterans offered such care. The sample consisted of 324 veterans (62% Operation Enduring Freedom [OEF]/Operation Iraqi Freedom [OIF]; 77% male; age M = 42.95, SD = 12.57 years), who attended an intake evaluation at a VAMC outpatient PTSD Clinical Team, were diagnosed with PTSD, and offered a course of EBP. Overall, 72% of veterans (n = 232) who were offered an EBP initiated such treatment, and 28% of veterans (n = 92) did not initiate treatment. Veterans who initiated treatment were significantly older. Treatment initiation did not significantly differ by ethnicity, gender, or baseline PTSD severity. Significantly more veterans referred from mental health clinics initiated treatment than did veterans referred from primary care. This study examined treatment initiation among veterans who were offered EBP for PTSD. Rates of initiation differed across subgroups of veterans. Clinically, this suggests the need to tailor outreach efforts to younger veterans, OEF/OIF veterans, and veterans referred from primary care, and potentially including programming and education aimed at primary care referrers, to increase help-seeking.