Tympanic membrane perforation (TMP) is a common pathology. Most TMPs heal spontaneously within 10 days. Those that fail to heal within three months are defined as chronic TMPs which surgical grafting is an option tor treatment, typically with autografts. The development of new graft materials for tympanic membrane repair requires in vivo (i.o. animal models) evaluations prior to clinical trials. In order to examine the efficacy of a novel graft, a chronic TMP animal model mimicking clinical condition of chronic TMPs Is required. The aim of this study was to develop techniques for creating a chronic TMP model in rats.