Isolated tricuspid insufficiency can be a well-tolerated lesion, as illustrated by a 32-year follow-up in one patient reported here. A second case of recent onset is also described. The 13 reported cases of isolated tricuspid insufficiency due to trauma can be divided into two groups: ruptured papillary muscle or ruptured chordae tendineae and/or valve. All patients with ruptured papillary muscle were dead or had surgery within 4 months after trauma. The earliest surgery in the chordae tendineae group was 1½ years after trauma. Physical findings in isolated tricuspid insufficiency are distinctive; the electrocardiogram usually shows incomplete right bundle-branch block, and the chest roentgenogram shows cardiomegaly. Indicator-dilution curves from the right atrium and pulmonary artery are useful for confirmation of the diagnosis. Surgery is indicated when papillary muscles are ruptured, but conservative treatment is probably usually indicated in the other patients.