Contrary to general opinion, the tricuspid valve remains a challenge in terms of its precise diagnosis, indications, and appropriate surgical treatment. This is due to: (1) its relatively low incidence, (2) its functions in a low pressure system, (3) its close relation to right ventricular function, and (4) it following the dictates of the left-side lesions. In an attempt to elucidate its present status, we reviewed our experience under several categories: (I) Incidence: Among the 1298 valvular patients operated in a period of 5 years (July 1988 to August 1993), 306 (23.6%) native tricuspid valves required surgery. Among the 899 patients with rheumatic etiology, tricuspid involvement was present in 249 (27.7%). (II) Pathology: Excluding other pathologies, organic rheumatic disease was present in 126 (50.6%) and functional regurgitation in 123 (49.4%). However, 45.3% of the organic tricuspids had a dilated annulus, suggesting the existence of organofunctional lesions. (III) Diagnosis: Although two-dimensional echo-Doppler is a reliable diagnostic method, only 41.7% of the organic lesions were diagnosed preoperatively and the remaining at surgery. (IV) Influence of left-side lesions: In a previous study we showed that the postoperative functional status and cardiac output were primarily related to the results of surgery on the mitral valve, irrespective of whether the tricuspid valve had been correctly or incorrectly repaired or even ignored. (V) Surgical techniques: Because of these reasons, evaluation of the individual superiority is difficult, but all annuloplasties result in a degree of residual stenosis (30% to 70% of patients) that is more pronounced in those with organic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)