The purpose of this study is to evaluate the influence of the age factor on the prognosis for tympanoplasty type I. One hundred subjects (41 males, 59 females, 16-65 years old, mean age 37.9 years old) who accepted tympanoplasty type I during a four-year period were reviewed. The success rate of the surgery was analyzed using the three criteria suggested by the Japan Clinical Otology Committee. In addition, linear regression was used to analyze the correlations between age and pre-operative hearing, post-operative hearing and hearing gain. Using the proportion of patients with a postoperative hearing threshold within 40 dB as the criterion, the 16-25 year-old group had the best results (80%) and the 56-65 year-old group had the worst results (66.7%). Using hearing gain exceeding 15 dB as the criterion, the best result was for the 36-45 year-old group (60.9%), and the worst result was for the 56-65 year-old group (26.7%). Using post-operative air-bone gap within 20 dB as the criterion, the best result was for the 16-25 year-old group (70%), and the worst result was for the 56-65 year-old group (40%). The best total success rate was for the 16-25 year-old group (80%) and the worst was for the 56-65 year-old group (66.7%). The total average success rate was 74%. Linear regression analysis showed that the postoperative hearing thresholds increased significantly with advancing age. But there was no statistically significant difference in hearing gain between the various age groups and the preoperative hearing thresholds also increased with advancing age. In conclusion, although tympanoplasty type I offered the patients a similar hearing gain among the different age groups, from the point of view of social function, it offered younger people a better chance of social hearing than the elderly and a higher surgical success rate. The poor postoperative hearing of the elderly was a result of their poor preoperative hearing condition.