The clinical data and presenting signs of 17 cases of atrial myxoma (14 left atrial, 3 right atrial myxomas) were analysed. The aim of the study was to assess changes in the presenting features since the introduction of non-invasive methods of cardiovascular investigation. Two groups of patients were identified according to whether the tumour has been diagnosed before (Group A) or after (Group B) the advent of echocardiography. The diagnosis of cardiac tumour, especially myxoma, has become easier with echocardiography and radio-isotope techniques. The presentation of myxoma, recognised earlier, has changed; the features of advanced valvular disease with resistant heart failure are no longer seen. Variable, atypical clinical signs are now encountered (syncope, pyrexia of uknknown origin, transient ischaemic attacks). The average delay between the first sign and diagnosis was 30 +/- 32 months in Group A, compared to 4,6 +/- 6,5 months in Group B (p < 0, 005). Of the 7 patients in Group B, three had normal cardiac auscultation, and normal ECG, and four had normal ESRs. The diagnosis of myxoma should be considered at the least doubt and an echocardiographic examination, preferably with 2-dimensional echo should be requested. It not only allows positive diagnosis but also orientates the patient to surgery without further investigation.