OBJECTIVES: To investigate the epidemiology, treatment patterns and associated medical expenses of diabetic macular edema (DME). METHODS: Data was collected and analyzed from 1 January 2004 to 31 December 2009 from Taiwan National Health Insurance Research Database, a source that covers more than 99% of Taiwan’s 23 million citizens. Study subjects were recorded as having DME according to ICD-9-CM codes. The 6-year trends in prevalence, treatment patterns and associated medical expenses of DME were retrieved and calculated from 2004 to 2009. Age, gender and treatment distribution of treated DME visual impairment patients were estimated in 2009. RESULTS: In 1.43 million diabetes mellitus population, 0.11 million patients (7.3%) have DME and 18.6 thousand patients (1.3%) have received treatment for DME visual impairment. The direct medical cost of DME patient was 3.1 times higher than the average national health expenditure per person (NTD 100,005 vs. NTD 32,240). Most treated DME visual impairment patients were older than 50 years. The male-to-female ratio was 1.05. There were 85.5% of treated DME visual impairment patients receiving laser treatment. Among them, there were 73.6% laser only and 11.9% laser plus intravitreous injection (IVI) combination. Average number of laser in current treatment pattern is three, and surgery (indicator of deterioration) proportion remains high despite current treatment. CONCLUSIONS: DME visual impairment patient population aligned with prevalence in other countries; 1.3% of DM patients treated with laser or IVI or vitrectomy in Taiwan. Medical claims data have shown that un-licensed use of intravitreal treatments in DME is increasing.