A study evaluating the durability of two recent techniques of tricuspid annuloplasty was conducted simultaneously in two institutions. One group working in Madrid, Spain, used Carpentier's ring in 32 patients. The other in Montreal, Canada, employed De Vega's semicircular annuloplasty in 17 cases. Competence of the tricuspid valve was obtained in nearly all cases at the time of surgery and persisted after a mean follow-up of 10.3 months (Madrid) and 11.5 months (Montreal) in 77 per cent of the cases. Light (1/3) residual tricuspid insufficiency was detected in 16.5 per cent; moderate (2/3) incompetence persisted in only 6.5 per cent. The majority of the patients with residual tricuspid insufficiency had unsuccessful or incomplete repair of left-sided heart lesions.