We aimed to test the hypotheses that Gulf War veterans who were older; had more severe symptoms; had more exposures during deployment; had increased psychological distress and believed they had 'Gulf War syndrome' would experience greater fatigue and poorer physical functioning at follow-up. Gulf War veterans who responded to an earlier retrospective cohort study were followed with a postal survey. Outcome was measured on the Chalder fatigue questionnaire, the General Health Questionnaire and the Medical Outcome Study Short-Form 36. Of those surveyed, 73.8% responded. Officer status was associated with a better outcome. A similar lack of association was found for exposures and physical functioning and GHQ-12 score. 'Gulf War syndrome' attribution was associated with a worse outcome for GHQ-12 and physical functioning even after controlling for severity of symptoms at baseline. This study suggests that while multiple vaccination and military exposures are important risk factors for the onset of symptoms in Gulf War veterans, these are not important risk factors for persistence of such symptoms. Instead the severity of the initial symptoms; psychological distress and attributions may be more important determinants of outcome.