Over 2 million US service members have now deployed to the Iraq and Afghanistan conflicts. Providers have consequently observed steep increases in mental health service use among these veterans. Dysregulation of the autonomic nervous system is thought to explain the physiological changes in patients with PTSD. This is the report of a patient whose nightmares were successfully treated with clonidine. Mr. F, a 48 years old man who developed PTSD symptoms after fighting in the Bosnian war for 15 months. He reported witnessing the loss of his family members and other relatives He was treated with venlafaxine XR 225 mg po q daily and olanzapine 10 mg po q daily without any relieve of his nightmares. He was later started on clonidine 0.1 mg po qhs. Within 2 weeks of starting clonidine, he reported improvement in the severity and duration of his nightmares and improved quality of his sleep. Clonidine a centrally acting alpha-agonist agent used to treat hypertension stimulates alpha-adrenoreceptors in the brainstem. This action results in reduced sympathetic outflow from the central nervous system. We hypothesize that this central mechanism of action is why clonidine may be more effective in treating nightmares in PTSD. Although, clonidine should be considered as an alternative in the treatment of nightmares among patients with PTSD, more clinical studies are needed to determine when to use clonidine.