Objective To review the clinical findings in the first 1000 veterans seen in the Ministry of Defence's Gulf war medical assessment programme to examine whether there was a particular illness related to service in the Gulf. Design Case series of 1000 veterans who presented to the programme between 11 October 1993 and 24 February 1997. Subjects Gulf war veterans. Main outcome measures Diagnosis of veterans' conditions according to ICD-10 (international classification of diseases, 10th revision). Cases referred for psychiatric assessment were reviewed for available diagnostic information from consultant psychiatrists. Results 588 (59%) veterans had more than one diagnosed condition, 387 (39%) had at least one condition for which no firm somatic or psychological diagnosis could be given, and in 90 (9%) veterans no other main diagnosis was made. Conditions characterised by fatigue were found in 239 (24%) of patients. At least 190 (19%) patients had a psychiatric condition, which in over half was due to post-traumatic stress disorder. Musculoskeletal disorders and respiratory conditions were also found to be relatively common (in 182 (18%) and 155 (16%) patients respectively). Conclusion Many Gulf war veterans had a wide variety of symptoms. This initial review shows no evidence of a single illness, psychological or physical, to explain the pattern of symptoms seen in veterans in the assessment programme. As the veterans assessed by the programme were all self selected, the prevalence of illness in Gulf war veterans cannot be determined from this study. Furthermore, it is not known whether the veterans in this study were representative of sick veterans as a group.