Objectives: Comparing serum and humor aqueous (HA) raftlin levels in diabetic patients and control group. Methods: In this prospective study, patients were divided into two groups diabetes mellitus (DM) and a control group. The DM group was divided into three subgroups. A total of 160 patients, including 35 without diabetic retinopathy (non-DR) (Group 1), 31 non-proliferative diabetic retinopathy (NPDR) (Group 2), 32 proliferative diabetic retinopathy (PDR) (Group 3), and 62 controls (Group 4), were included in the study. Venous blood and HA samples were taken from the patients and their raftlin levels were measured. Results: Serum raftlin levels were decreased in the DM main group (p=0.046) but there was no significant difference in HA raftlin levels (p=0.838). There was no significant difference between the subgroups (Groups 1, 2, 3, and 4) in terms of serum and HA raftlin levels. Diabetic macular edema (DME), anti-vascular endothelial growth factor (anti-VEGF), and panretinal photocoagulation (PRP) application were not found to be associated with raftlin levels in Group 3. A moderate positive correlation was found between serum and HA raftlin levels (r=0.491). There was a negative correlation between serum raftlin levels and serum glucose levels (p=0.05). No correlation was found between serum and HA raftlin levels and serum leukocyte and lipid levels (p>0.05). Conclusions: In our study, raftlin levels were examined for the first time in DM patients and it was observed that serum raftlin levels were negatively correlated with glucose levels. Raftlin molecule may be involved in the etiology of DM through VEGF.