Examined the degree to which Persian Gulf War veterans present for clinical assessment, and compared findings with a subset of veterans voluntarily attending a medical assessment program (MAP). 3,529 United Kingdom Armed Forces personnel (aged 25-58 yrs) who served in the Persian Gulf conflict completed questionnaires concerning demographic characteristics, symptoms, health perceptions, physical functioning, psychological distress, posttraumatic stress symptoms, and health attributions. 173 of these Ss had previously attended a MAP. Results show that MAP Ss were more likely to be female, older, and working part time or not working at all. MAP Ss exhibited poorer health perceptions and reported higher levels of illness, and they differed in terms of their health attributions. The perception of having Gulf War syndrome and attributing health problems to Gulf War service were the most powerful predictors of MAP attendance, even when controlling for physical functioning level. It is concluded that health beliefs rather than symptoms are more important predictors of attendance of MAPS, and that Gulf War veterans who attend MAPs have different characteristics than those who do not. MAP patients are unrepresentative of the wider deployment to the Persian Gulf.