The in vitro hemodynamic behavior of a bovine pericardium xenograft with discontinuity of the annular support, named the "Less Stented" bovine pericardial xenograft, was analyzed. A "Less Stented" bovine pericardial xenograft consisting of a glutaraldehyde-treated bovine pericardium prosthesis manufactured in Braile Biomédica Ltd, São José do Rio Preto, São Paulo, Brazil, was used according to the same protocols of the stented bioprosthesis manufacturer. Bovine pericardial xenografts were tested in a pulse simulator and analyzed in a cardiac simulator, with respect to the transvalvular gradient, regurgitant fraction and leakage volume, discharge coefficient, performance, and efficiency index. Analyses were performed by Pearson's correlation test and simple linear regression. The transvalvular gradients ranged between 6.37 and 11.62 mm Hg with a mean flow between 4.39 and 7.96 L/min, giving a good correlation (0.8291) on the regression curve with an increase in flow. The regurgitant fraction ranged between 10.95 and 17.94% and leakage volume between 4.49 and 7.87%. The discharge coefficient, performance, and efficiency index showed favorable behavior with the flow increase, with good correlation coefficient (0.9385, 0.9332, and 0.9024, respectively). The initial results of the "Less Stented" bovine pericardial xenograft size 25 analyses demonstrated a satisfactory in vitro performance. Evaluations of the hemodynamic performance of small size "Less Stented" bovine pericardial xenograft should be made to clarify the biological behavior of this new xenograft.