We performed prosthetic valve replacement with skirt in 11 patients for the fragile valvular annulus. Subjects included 6 patients with active infective endocarditis involving aortic root abscess, 2 patients with systemic disease requiring steroid treatment, and 3 patients with hemolysis or perivalvular leakage. Operative procedure in 11 patients was performed aortic valve replacement with Dacron or Xenomedica skirt attached to the prosthetic ring. One patient died of heart failure during perioperative period. 2 patients died of arrhythmia, heart failure in late postoperative period. The event free rate was 77.1% since 5 years after operation. We conclude that prosthetic valve replacement with skirt is useful to tha fragile valvular annulus.