Twenty-nine patients were investigated in order to assess diagnostic possibilities of ultrasonic investigation with regard to tricuspid incompetence. Three highly specific and fairly sensitive criteria of trans-tricuspid regurgitation were identified in addition to a series of indirect echographic signs of tricuspid incompetence. Ultrasonic investigations of the heart, such as one- and two-dimensional and, particularly, contrast echocardiography, are fairly reliable instruments of the preoperative diagnosis of tricuspid incompetence.