Introduction <p>In the pilot study our aim was to observe the role of platelet membrane selectin (P-sel) and soluble platelet selectin (sP-sel) as risk factors for diabetic retinopathy. Our study is based on observations that have not previously been reported by other authors.</p> Subjects and methods <p>The pilot study enrolled 49 patients with type 2 diabetes with and without retinopathy who attended regular ophthalmological screening due to their diabetes mellitus at the outpatient care facility of the Department of Ophthalmology, University of Debrecen. Analysis of P-sel by flow cytometry was performed, and the plasma levels of sP-sel were determined.</p> Results <p>The mean fluorescence intensity of P-sel was significantly higher in the non-proliferative retinopathy group, compared to the control group (<i>p</i> = 0.037) and the no-retinopathy group (<i>p</i> = 0.039), and was found to be lower in the proliferative retinopathy group, compared to the non-proliferative group. Soluble P-sel significantly increased in patients with diabetic retinopathy (<i>p</i> = 0.044).</p> Discussion <p>P-sel can lead to impairment in blood circulation on both the arterial and venous side, which contributes to the development of non-proliferative diabetic retinopathy. Upon the appearance of proliferation, it may lose its pathogenetic role. Soluble P-selectin can play a role in the development of any diabetic retinopathy, which is likely to occur through arteriolosclerosis-induced hypoxia.</p>