Although cognitive-behavioral therapy (CBT) is an effective treatment for posttraumatic stress disorder (PTSD), many patients fail to attain remission with CBT. The authors propose augmentation of CBT with oxytocin in the treatment of PTSD. Oxytocin has a combination of pharmacologic effects that result in a “sense of safety” for the patient, which is a prerequisite to successful treatment of PTSD. We suggest a dual explanatory mechanism as to why oxytocin may be effective: through a reduction of fear response (decreasing amygdala activation, inhibiting fear response, and enhancing extinction learning) and through an increase of social interaction (activating social reward-related brain regions increasing engagement in the therapeutic alliance). Given that PTSD is marked by deficits in anxiety/stress regulation and in social functioning, and that oxytocin is implicated in both of these areas, oxytocin seems a likely candidate for treatment of patients with PTSD. Further clinical studies of the therapeutic value of oxytocin are indicated.