To report the findings at 1 year of a study comparing repeated intravitreal bevacizumab (ivB) and modified Early Treatment of Diabetic Retinopathy Study (ETDRS) macular laser therapy (MLT) in patients with persistent clinically significant diabetic macular edema (CSME).Prospective, randomized, masked, single-center, 2-year, 2-arm clinical trial.A total of 80 eyes of 80 patients with center-involving CSME and at least 1 prior MLT.Subjects were randomized to either ivB (6 weekly; minimum of 3 injections and maximum of 9 injections in the first 12 months) or MLT (4 monthly; minimum of 1 treatment and maximum of 4 treatments in the first 12 months).The primary end point was the difference in ETDRS best-corrected visual acuity (BCVA) at 12 months between the bevacizumab and laser arms.The baseline mean ETDRS BCVA was 55.7+/-9.7 (range 34-69) in the bevacizumab group and 54.6+/-8.6 (range 36-68) in the laser arm. The mean ETDRS BCVA at 12 months was 61.3+/-10.4 (range 34-79) in the bevacizumab group and 50.0+/-16.6 (range 8-76) in the laser arm (P = 0.0006). Furthermore, the bevacizumab group gained a median of 8 ETDRS letters, whereas the laser group lost a median of 0.5 ETDRS letters (P = 0.0002). The odds of gainingor =10 ETDRS letters over 12 months were 5.1 times greater in the bevacizumab group than in the laser group (adjusted odds ratio, 5.1; 95% confidence interval, 1.3-19.7; P = 0.019). At 12 months, central macular thickness decreased from 507+/-145 microm (range 281-900 microm) at baseline to 378+/-134 microm (range 167-699 microm) (P0.001) in the ivB group, whereas it decreased to a lesser extent in the laser group, from 481+/-121 microm (range 279-844 microm) to 413+/-135 microm (range 170-708 microm) (P = 0.02). The median number of injections was 9 (interquartile range [IQR] 8-9) in the ivB group, and the median number of laser treatments was 3 (IQR 2-4) in the MLT group.The study provides evidence to support the use of bevacizumab in patients with center-involving CSME without advanced macular ischemia.