OBJECTIVES: Acute otitis media (AOM) is the most common childhood infection next to common cold. The impacts of AOM deserve attentions from both public health and economic perspectives. Taiwan’s National Healthcare Insurance (NHI) provides comprehensive coverage and to date, over 97% of the populations are insured. In this study we use the NHI claim database to evaluate the economic impacts of AOM. METHODS: We reviewed the claims of pediatric patients with AOM who had received treatment during January 1 - December 31, 2006. Numbers of visits and expenses (in $New Taiwan Dollars, exchange rate with $USD 32~33.5 during year 2006) were calculated. The data size is around 400 gigabytes.   RESULTS: The mean age of disease was 5.4 years-old. With 29.6 % under 3 years-old, 48.1% under 7 years, and 22.3 % under 12 years-old. The male: female ratio was: 1.2:1. There were 733,546 visits related to the occurrence of AOM, 717,263 (visits) occurred in outpatient settings; 16,283 admissions were related to AOM care. A total of 45.8% (328,517 out of 717,263 visits) were treated by pediatricians, 35.2% (252,347 visits) were treated by otolaryngologists, and 4.6% (34,840 visits) were treated by family practitioners. Around 97.0% (15,799 out of 16,283 admissions) were under pediatric and 1.7% (281) were under otolaryngology services. The total annual expenses related to AOM care was 554,507,868 $NTD, comprising of 315,671,421 $NTD in outpatient (56.9%), and 238,836,447 $NTD in inpatient cares (43.1%). In average, AOM took 3.6 antibiotics-days, and 4.5 admission-days to treat. CONCLUSIONS: Over half of the AOM care expenses were spent in ambulatory services. Pediatricians took 46% outpatient and 97% inpatient AOM care resources. The nation-wide economic impact of AOM was around 0.55 billion $NTD annually. The NHI claim database provides possibility for further economic analysis.