Many service members returning from Iraq and Afghanistan have difficulties adjusting back to civilian life. Research shows that symptoms of posttraumatic stress disorder (PTSD) are particularly high in returning Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) veterans, and that combat-related nightmares and sleep disturbances are common in veterans with PTSD. This is of concern because people with these problems will often use unhealthy ways of coping. Although combat-related nightmares and difficulty sleeping are highly distressing, there are helpful treatments that do not involve taking medication. One of these treatments teaches specific skills to help people improve their sleep habits and to change their nightmares so that they are less upsetting. This treatment can be very helpful and research shows that people experience decreases in the frequency and severity of their nightmares, decreased symptoms of depression and PTSD, and improved sleep quality and quantity after completing treatment. However, because this treatment has only been studied with civilians, it is not clear how well this treatment works for returning veterans. This study tests how well this treatment works in treating combat nightmares in veterans who also have PTSD from experiencing a traumatic event.