Artificial eardrums made from biodegradable poly(D,L-lactic acid), poly(glycolic acid) and poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50, and made from the microporous poly(tetrafluoroethylene) and bisphenol-A poly(carbonate) membranes were implanted into the ear and as a reference subcutaneously in rats. The implants were histologically examined for periods up to one year. From the biodegradable polymers studied the poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50 evoked the least tissue reaction and the newly formed tympanic membranes are the best in terms of thickness and overall integrity. The microporous poly(tetrafluoroethylene) membrane can be considered as a valuable support for the formation of a reinforced tympanic membrane.