Abstract: AIM: To evaluate the cytotoxicity of acellular porcine heart valve treated with dye-mediated photooxidation. METHODS: L929 cells were cultured in the extraction obtained from acellular porcine heart valve with dye-mediated photooxidation to measure the relative growth rate by methyl-thiazolyl-tetrazolium (MTT) assay. L929 cells were cultured directly with acellular porcine heart valve with dye-mediated photooxidation. Cell morphology was observed and the cell number was counted. Morphology of L929 cells cultured on the surface of acellular porcine heart valve with dye-mediated photooxidation was examined by scanning electron microscopy. RESULTS: The property of acellular porcine heart valve with dye-mediated photooxidation was stable. Toxic levels ranged from grade 0 to I . There were no signs of cytotoxicity induced by acellular porcine heart valve with dye-mediated photooxidation, and cell morphology was normal. CONCLUSION: Acellular porcine heart valve with dye-mediated photooxidation shows good cytocompatibility in vitro.