Diabetic macular edema is the leading cause of moderate visual deterioration in patients with diabetic retinopathy. Ranibizumab) blocks vascular endothelial growth factor (VEGF) induced hyperpermeability of blood vessels. In this prospective case series we investigated the efficacy and safety of anti-VEGF treatment in reduction of central retinal thickness (CRT) and improvement in visual acuity (VA) in patients with diabetic macular edema (DME). 9 patients were followed up for 6 months and treated monthly with intravitreal ranibizumab. VA and CRT were measured at each visit. Treatment was discontinued as the peak improvement of either parameter was reached and reinstituted in case of deterioration/recurrence of edema. Study endpoints included: VA using ETDRS chart, CRT and number of injections at 6 months. Mean VA from all 9 patients increased by 0.3 lines of logMAR (p < 0.05 compared to baseline), and CRT decreased from 515 +/- 123 microm to 310 +/- 110 microm. The improvement of VA after ranibizumab injection was in correlation with a decrease in CRT. Mean of 4 injections were needed to control the disease during the follow-up period. Ranibizumab treatment was effective in VA and reducing CRT. Several injections were needed to control the disease. Regular OCT examinations and retreatment are advised in order to maintain initially reached VA.