From March 1992 to August 1993, 50 patients underwent mitral valve replacement with the new heterologous stentless mitral bioprosthesis in our institution. The development of this heart valve substitute, its technique of implantation and the results observed in the first group of 50 patients have had us to review the initial experience. The surgical protocol included an accurate mitral valve complex analysis, adequate valve size selection, attachment of the papillary muscle to the new chordal origin and approximation of the stentless mitral to the patient's annulus. There was one hospital death (2%), not related to the valve or to the technique and four reoperations: two due to endocarditis, one because of a perivalvular leak and one due to a mismatched stentless valve. The late mortality (4%) was not valve-related. The follow-up has shown excellent valve performance with improved left ventricular function in the great majority of the patients. Based on the current analysis, it can be stated that reproducibility of the surgical technique and the excellence of the clinical follow-up may contribute favorably to a better quality of life and longer valve durability in patients requiring mitral heart valve replacement.