Abstract: Posttraumatic stress disorder (PTSD) is common among U.S. military veterans and is associated with increased risk of suicidal thoughts and behaviors. Crisis response planning (CRP), a brief safety planning-type intervention, has been shown to rapidly reduce suicidal ideation and suicide attempts in emergency and acute care settings. CRP's effectiveness when combined with trauma-focused therapies remains unknown. In this randomized pragmatic clinical trial with one-year follow-up, 157 U.S. military personnel and veterans were randomly assigned to receive CRP or self-guided safety planning (SP) prior to beginning massed cognitive processing therapy (CPT) for PTSD. Among 51 (32.5 % of sample) participants endorsing suicidal ideation at baseline, reductions in the severity of suicidal ideation were significantly larger and faster in CRP (F(11,672)= 15.8, p < .001). Among 106 participants denying suicidal ideation at baseline, 8.5 % of CRP participants versus 11.9 % of SP participants (OR=0.69, 95 % CI=0.19-2.52) reported new-onset suicidal ideation during any follow-up assessment. PTSD symptoms significantly reduced over time with no differences between groups. Results support the effectiveness of CRP for rapidly reducing suicidal ideation and managing suicide risk during outpatient treatment for PTSD.