Native heart valve leaflets are subjected to continuous pulsatile and homodynamic forces and can be as thin as 300 mu m. For a proper function of the valve the materials selected for the leaflets need to be biocompatible, robust, flexible, and have comparable mechanical properties to the natural ones. In this paper, biocompatibility and cell retention ability for gelatin-chitosan polyurethane (PU), polyglycolide (PGA)/PLA and collagen-coated bovine pericardium were examined and their mechanical properties were tested. Endothelial cells, isolated from ovine carotid arteries were seeded onto these materials and exposed to a range of shear-stresses for a period of 1-3 h. The findings indicated that throughout the exposure time and the shear-stress range tested, a mean cell retention rate of 80% was obtained in the gelatin-chitosan PU group. However, for PGA/PLA and pericardium groups it was found that as the exposure time of shear-stress increased, a significant cell reduction was observed. Noticeably for all the range of physiological flow conditions tested, the electrospun gelatin-chitosan PU demonstrated good biocompatibility and cell retention properties and could be potentially used as a biomaterial for tissue engineering of heart valves.