Objective: Veterans suffering from posttraumatic stress disorder (PTSD) may avoid or fail to follow through with a full course of face-to-face mental health treatment for a variety of reasons. We conducted a pilot effectiveness trial of an online intervention for veterans with current PTSD to determine the feasibility, safety, and preliminary effectiveness of an online writing intervention (i.e., Warriors Internet Recovery & EDucation [WIRED]) as an adjunct to face-to-face psychotherapy. Method: Veterans (N = 34) who had served in Iraq or Afghanistan with current PTSD subsequent to deployment-related trauma were randomized to Veterans Affairs (VA) mental health treatment as usual (TAU) or to treatment as usual plus the online intervention (TAU + WIRED). All research participants were recruited from the Trauma Services Program, VA Medical Center, Washington, DC. They completed baseline assessments as well as assessments 12 weeks and 24 weeks after the baseline assessment. The online intervention consisted of therapist-guided writing, using principles of prolonged exposure and cognitive therapy. The intervention was adapted from an evidence-based treatment used in The Netherlands and Germany for individuals who had been exposed to nonmilitary traumas. Results: In addition to showing that the online intervention was both feasible to develop and implement, as well as being safe, the results showed preliminary evidence of the effectiveness of the TAU + WIRED intervention in this patient population, with particular evidence in reducing PTSD symptoms of hyperarousal. Conclusion: With minor modifications to enhance the therapeutic alliance, this intervention should be tested in a larger clinical trial to determine whether this method of online intervention might provide another alternative to face-to-face treatment for veterans with PTSD.