In a total of 38 operative survivors who underwent tricuspid annuloplasty for functional tricuspid regurgitation, Kay-Boyd's, DeVega's and Carpentier's methods were compared using a newly developed radioisotope technique together with routine examinations. Carpentier's ring method was most effective for all grades and types of regurgitation. Kay-Boyd's method usually left some residual regurgitation and DeVega's semicircular annuloplasty had unpredictable results. Although the results of tricuspid annuloplasty are influenced by the quality of the repair of the primary lesion as well as the technique of tricuspid annuloplasty itself, we recommend Carpentier's method in the first place. However, further study is mandatory for a definite conclusion.