A long-term follow-up was performed of 540 myringoplasties that were considered to be successful 3 months after operation. The ears were observed to 12 years, and it was found that 70.8% of the eardrums were intact, fully epithelialized, and without retraction. In 22.4% success was only partial, because there was a small reperforation, a slight retraction of the eardrum, or an epithelial defect. In 7.6% of the eardrums deterioration occurred over the years, for the above three reasons, to a degree that turned an initial successful outcome of the operation into a failure. Of the various factors that characterized and accompanied the initial perforation before the operation, or the various operative technical aspects, none was found to influence the late outcome of myringoplasty. An exception was the anterior perforation, in which prognosis was less favorable than in any other perforation. During our continuous follow-up about a fourth of the reperforations perforated spontaneously and silently, some doing so several times over and over. This particular phenomenon could bear on the etiology of the group of tympanic membrane perforations that has no obvious inflammatory or traumatic history.