Background: Intravitreal bevacizumab has been shown to be an effective treatment of diabetic macular edema (DME). Purpose: To assess the effect of intravitreal bevacizumab (Avastin) on visual acuity and macular thickness in patients with DME. Methods: A retrospective, cross sectional study reviewed the clinical records of 130 patients with center-involved DME. 132 eyes of 81 patients who received a single intravitreal injection of bevacizumab in a dose of 0.05ml either alone or with laser therapy were included in the final analysis. Each patient underwent a detailed ophthalmic examination, including best-corrected visual acuity (BCVA) and retinal thickness measurement by optical coherence tomography (OCT), at baseline and at last follow up visit. Results: In this study, 132 eyes of 81 patients with diabetic macular edema were studied. 51 (63%) were males and 30 (37%) were females. The age range was from 40 to 70 years with a mean of 58.2 ± 9.4 years. All patients completed 6 months of follow-up. mean visual acuity (VA) improved from 0.80 to 0.60 at 6 months and the mean central macular thickness (CMT) was 459.13±157.92 μm at baseline and it decreased significantly to 330.21± 164.06 μm (p<0.001) at 6 months. Conclusion: Intravitreal bevacizumab results in significant visual improvement and reduction in macular edema in patients with DME at 6 months follow up.