Background and aim: Diabetic retinopathy (DR) and maculopathy are major tragedies in ophthalmology. Lipoprotein (Lp) (a) is a pro-atherogenic and pro-thrombotic risk factor. It has an antifibrinolytic effect with increasing risk of clotting and blood vessel occlusion. Elevated Lp(a) concentrations can also damage the microcirculation by its oxidative effect. The aim of this study was to investigate the relationship between serum level of Lp(a) and developing maculopathy in diabetic patients by measuring central macular thickness (CMT) using Optical Coherence Tomography (OCT). Methods: Case-control study included one case group of 40 eye of 20 diabetic patients and one control group of 40 eyes of 20 non-diabetic age and gender matched controls. All the participants were subjected to full ophthalmological examination with best corrected visual acuity (BCVA) testing, Body Mass Index (BMI) calculation, glycosylated hemoglobin (HbA1c), serum Lp (a) and CMT measurement by 3D OCT. Results: There was no significant difference between the two groups regarding age or gender. Cases group had significantly higher BMI, HbA1c, LP (a) and CMT than control group (p