History and Objectives: Due to the prevalence of otitis media among children and Due to the importance of diagnosis with tympanometry among these patients and since various reports imply different results obtained from the instrument and in order to assess the diagnostic power of the instrument among patients with otitis media with fluid, the present investigation was carried out on patients referred to the Taleghani hospital in Tehran in 1996.

Materials and Methods: A diagnostic clinical trial was carried out on patients suspected of the disease and diagnosed with tympanometry model AZ-7 (Intra-acustic, Denmark). Projects importance was explained to the patients and written consent was obtained. Tympanometry was again performed before surgery without N2O administration. During the anesthesia mirenectomy was performed. Final diagnosis was based on the observation of fluid and it’s the positive predictive value.

Results: The study was carried out on 18 individuals (9 females and 9 males) with mean age of 8.2±3.1 years and overall 33 ears were examined. During operation in 7 cases (21.2%) no fluid was observed and in 26 ears fluid was observed and in 3 cases (11.5%) serous fluid was detected and in 23 of cases (88.5%) glue was observed. The positive predictive value of tympanometer was 79%.

Conclusion: Due to the presence of the false positive cases and well-known side effects of myringodectomy, the use of tympanometry in diagnosis of OME is not suggested. Further research is suggested.