Pericardium is commonly used for repair of congenital heart defects [Paez, 1999]. Autologous pericardium can be used in its fresh non-treated state, or after chemical fixation with glutaraldehyde solution as a biomaterial for surgical repair of congenital heart anomalies. However, there are not many studies about changes of biomechanical properties of human pericardium after treating with glutaraldehyde. Influence of different concentration and exposition time of glutaraldehyde on resistance of human pericardium to proteolytic degradation needs further investigations. [Vincentelli, 1998, Stacchino, 1998] The aim of this experimental study is to investigate changes of biomechanical properties and resistance to proteolytic degradation of human pericardium, which was used as patch material for congenital heart surgery, after harvesting and treatment with glutaraldehyde solution.