AIM: To evaluate the retinochoroidal microvascular circulation and anatomical structure of diabetic and non-diabetic patients with epiretinal membrane (ERM) with the help of optical coherence tomography angiography (OCT-A) and compare them with healthy control subjects. METHODS: In this prospective, cross-sectional study, a total of 165 eyes were evaluated, including 50 eyes of patients with diabetic ERM, 54 eyes of idiopathic ERM (iERM) patients, and 61 eyes of healthy controls. Macula and disc angiography was performed by OCT-A. Macular vessel density (VD) ratio was evaluated by dividing the VD of the foveal region by the VD of the parafoveal region. Statistical calculations were evaluated at the 95% confidence interval. RESULTS: Macula superficial VD values of ERM cases were lower than that in the control group, while foveal VD was higher in ERM cases. Macula deep VD values of ERM cases were lower in all quadrants, except the fovea. The width of the foveal avascular zone (FAZ) area was significantly lower in the ERM groups, and the FAZ width was lowest in iERM group. Macula superficial VD ratio was significantly higher in the ERM groups, but there was no significant difference between ERM groups. Macula deep VD ratio was significantly higher in the iERM group than in the control group. CONCLUSION: Diabetic and idiopathic ERMs differ in their mechanism of formation and clinical presentation, as well as their effect on retinal vascular structures. If the relationship of increase of retinal thickness with vascular integrity can be demonstrated with OCT-A, then, OCT-A can be used as a guide for ERM prognosis.