To investigate the effect of age on aflibercept (Eylea) response in macular edema secondary to treatment-naive diabetic eyes. Two hundred seventy-three eyes of 273 treatment-naive patients with macular edema secondary to diabetes mellitus were enrolled in this study. The patients in the study were divided into the following 4 groups according to their ages: Group 1 (40-50 years), Group 2 (51-60 years), Group 3 (61-70 years), and Group 4 (>70 years). Three consecutive injections at intervals of 1 month were applied to all diabetic patients. The efficacy of the aflibercept treatment on macular edema according to age groups was assessed by optical coherence tomography by comparing the central foveal thickness (CFT) values and mean visual acuity changes after initial and three loading dose injections. After three consecutive aflibercept injections, the mean reduction of CFT in Groups 1, 2, 3, and 4 were -256.4 ± 110.9, -197.4 ± 96.4, -189.4 ± 110.8, and -186.2 ± 118.9 µm, respectively. The changes of CFT was significantly different between age groups (P = 0.003, analysis of covariance). The improvement of visual acuity was significantly different in each group (P < 0.001 in all groups, paired-samples t-test), and changes of visual acuity was significantly different between age groups (P < 0.05, analysis of covariance). In addition, ages of patients were correlated with the mean reduction of CFT and mean improvement of visual acuity for the whole study group (r = -0.183, P = 0.002 for CFT; r = -0.682, P < 0.001 for visual acuity, Pearson correlation). In this study, it was observed that the efficacy of aflibercept treatment was found to be more effective in younger patients in treatment-naive diabetic macular edema patients.