Aim The aim of this study was to evaluate the effect of intravitreal Bevacizumab injection at the time of phacoemulsification on the incidence of postoperative diabetic macular edema (DME) in diabetic patients without preexisting DME. Patients and methods The study included 40 diabetic patients with no preexisting DME who underwent phacoemulsification. They were divided into two groups: group A (controls) included 20 eyes in which phacoemulsification was performed without Bevacizumab injection and group B (Bevacizumab): included 20 eyes in which 1.25 mg Bevacizumab was injected at the conclusion of surgery. Macular optical coherence tomography and visual acuity were assessed at 2 weeks, 2 months, and 6 months postoperatively. Results The incidence of DME in the noninjected patients was 5, 20, and 30% at 2 weeks, 2 months, and 6 months, respectively, compared with 0, 5, and 5% in the Bevacizumab injected patients. This difference in incidence was only statistically significant at 6 months (P=0.15 at 2 months and 0.04 at 6 months). On comparing the baseline central macular thickness in the control and Bevacizumab groups (229.4±26.8 and 230.8±26.7 μm, respectively) to the 6-month follow-up values (278.3±52.3 and 254.7±26.2 μm, respectively), a higher statistically significant difference was found in the control group (P=0.0001) versus the injected group (P=0.002) denoting more progression of DME in the control group. Conclusion Prophylactic intravitreal injection of Bevacizumab at the time of phacoemulsification is potentially effective in the midterm prevention of DME in cases with and without preoperative diabetic retinopathy.