BACKGROUND AND AIMS: Angiography permits an evaluation of the morphology of the coronary artery, stratification of risk and optimal therapeutic management in patients with suspected coronary artery disease (CAD). The sophisticated apparatus, cost and invasiveness of the procedure necessitate well-considered application of this method. In spite of an exact documentation of the patient's medical history and careful establishment of the indication, the results of angiography are often normal. Therefore, it appears important to analyse the referral diagnoses in patients with normal coronary angiograms. PATIENTS AND METHODS: We studied 1000 consecutive patients (625 men, 375 women, mean age 63.1 years) who underwent coronary angiography at our institution from January to May 1998. All patients were included in the retrospective analysis of the referral diagnoses. RESULTS: 875 patients (554 men, 321 women) were referred due to suspected CAD; 173 of these had normal angiographic findings (20%; 73 men, 100 women; mean age 58.4 years). The referral diagnoses were as follows: unstable angina in 62 patients (36%), stable angina in 40 patients (23%), chest pain and pathological findings of non-invasive testing in 32 patients (19%), atypical chest pain in 25 patients (14%), previous myocardial infarction and multiple risk factors in 7 patients each (4% each). Gender-related differences were remarkable. Only 73 of the 554 referred men (13%) had normal angiographic findings, whereas in women the rate of normal results was more than twofold higher, i.e. 100 of the 321 referred women (31%) had normal angiographic findings (p < 0.01). CONCLUSIONS: Among 875 patients referred to our catheter laboratory for coronary angiography due to suspected CAD, normal angiographic results were documented in 20%. The high frequency of the referral diagnosis 'unstable angina' and 'pathological result of noninvasive testing' was as remarkable as the high proportion of women among patients with normal findings.