The diagnosis of atrial myxoma, the most common cardiac tumour, has been greatly facilitated by the introduction of echocardiography. The principal echocardiographic features and the diagnostic pitfalls encountered in a personal series of 7 atrial myxomas (5 left and 2 right) studied by M mode and 2-dimensional echocardiography are reported. In M mode, left atrial myxoma is a relatively easy diagnosis when the tumour prolapses into the mitral orifice. On standard mitro-aortic scanning, it is recorded behind the anterior mitral leaflet as a mass of abnormal echos appearing shortly after mitral valve opening. The diagnosis is much more difficult or even impossible in nonprolapsing tumours. Right atrial myxomas, prolapsing into the tricuspid orifice, do not usually pose any diagnotic problems. 2-dimensional echocardiography shows its superiority in the early diagnosis of small, localised, relatively immobile and non-prolapsing tumours. The parasternal (long axis and transverse views), the apical (4 and 2 chamber views) and subxiphoid positions were the most useful incidences and the tumour was visualised as a more or less circumscribed mass of echos. In all cases, 2-dimensional echo provided information on the size, mobility, insertion and the length of the pedicle of the tumour. Atrial myxoma is being recognised more easily and more often nowadays by echocardiography, the diagnostic method of choice, and 2-dimensional studies should be preferred.