PURPOSE: The purpose of this study was to evaluate the biodegradation and biocompatibility of poly L-lactic acid (PLLA) implantable mesh under in vitro and in vivo conditions. METHODS: PLLA mesh was examined for changes in weight and tensile strength. The histology of the tissue around the PLLA implant was also evaluated. RESULTS: The weight and tensile strength of the PLLA prosthesis was stable for 180 days. In addition, the surface of the PLLA mesh was not digested under in vitro or in vivo conditions as determined by scanning electron microscope. Histologically, there were no significant changes in the diameters of implanted PLLA mesh and subtype fibers over the course of 180 days. Likewise, there were no significant changes in the number of inflammatory and mast cells after 180 days, nor was there an increase in the percentage of collagen surrounding the PLLA mesh. CONCLUSIONS: The results indicate that PLLA prostheses have good rigidity and biocompatibility in vivo and in vitro.