In a series of 103 consecutive surgical patients, the normal and pathological echocardiographic appearances of the tricuspid valve were analysed and compared with the anatomical findings. It was possible to define the nature of the lesions by echocardiography, which was superior to angiography in this field. The right ventricular index (right ventricular dimension body surface area) correlated well with the mean pulmonary artery pressure (r = 0.75; p less than 0.001). The index may be useful in the long term follow-up of post-operative patients.