OBJECTIVES: To characterize the economic and societal burden of Diabetic Macular Edema (DME) in Canada. METHODS: Patients with clinically significant macular edema (CSME) were enrolled by ophthalmologists or retinal specialists across Canada. Patients are followed over a 6-month period to combine prospective data collected during monthly telephone interviews and at sites at months 0, 3 and 6.  Visual acuity (VA) is measured and DME-related health care resource information is collected.  Patient health-related quality of life is measured using the National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25), and the EuroQol Five Dimensions (EQ-5D). The 3-month results are available and presented here. RESULTS: A total of 145 patients [mean age 63.8 years (range: 30-86 yrs); 52% male; 81% Type 2 diabetes; mean duration of diabetes 18 years (range: 1-62 yrs); 72% bilateral CSME] were enrolled from 17 sites across 6 provinces in Canada.  At baseline, the mean VA was 20/60 (range: 20/20-20/800) across all eyes diagnosed with CSME (249 eyes).  Sixty-eight percent of patients had VA severity in the worse seeing eye of normal/mild vision loss (VA 20/10 to ≤ 20/80), 19% moderate vision loss (VA > 20/80 to ≤ 20/200), and 13% severe vision loss/nearly blind (VA > 20/200).  At month 3, the mean NEI VFQ-25 composite score was 79.9, the mean EQ-5D utility score was 0.79, and the EQ visual analogue scale score was 70.6.  The average 3-month DME-related cost per patient was $1,487 across all patients (95% confidence interval: $1,164 to $1,810).  The cost was $1,390 for patients with normal/mild vision loss, $1,831 for patients with moderate vision loss, and $1,467 for patients with severe vision loss/nearly blind.   CONCLUSIONS: DME is associated with limitations in functional ability and quality of life. In addition, the DME-related cost is substantial to the Canadian health care system.