Study Abstract: This trial was a study of Gulf War era veterans who have unexplained chronic medical symptoms such as pain, fatigue, and/or cognitive difficulties. All Gulf War veterans who were deployed to the South West Asia theater of operations between August 1990 and August 1991 were eligible for the study if they had at least two of the following three symptoms that began after August of 1990, lasting for more than six months and occurring up to present: 1. fatigue that limits usual activities (work, recreation, or social), 2. musculoskeletal pain involving two or more regions of the body, and neuro-cognitive dysfunction (self-reported difficulties in memory, concentration, or attention). Veterans who met enrollment criteria were randomized to one of four treatment arms: 1. CBT plus aerobic exercise, 2. aerobic exercise alone, 3. CBT alone, and 4. usual and customary care. Treatment was given for three months in group format. The CBT and exercise groups met for one hour, once a week for 12 weeks for a total of 12 hourly sessions. The interventions were standardized and all investigators were trained in the use of these methods prior to start up of the trial. The target sample size was 1064 veterans with GWVI to be accrued from 20 Medical Centers (18 VA and 2 DOD). All veterans were followed for one year and outcomes measured at 3 months (immediately following the end of treatment), 6 months and 12 months after enrollment.