This short-term prospective study involved echocardiographic assessment of hemodynamic performance at 1 and 3 months postoperatively, of a new stentless quadrileaflet bovine pericardial mitral valve implanted in 22 patients at one center. Postoperatively, the mean pressure gradient across the prosthesis ranged from 1.7 to 2.2 mmHg. The effective orifice area measured 2.4 ± 0.7 cm² using the Hatle equation, compared with 1.8 ± 0.5 cm² by the continuity equation (p <0.005). At 3 months after surgery, mitral regurgitation was trivial in 77% of cases and mild in 14%; moderate mitral stenosis was noted in one patient. Cardiac index improved significantly postoperatively (p <0.005). All patients were symptomatically improved and the hemodynamic performance of this novel valve proved satisfactory.