Background and Objectives: Zonulin is a molecule that has been identified as an intestinal permeability marker in recent years. Zonulin previously linked to Diabetes Mellitus, Obesity and Cardiovascular Disease but but its role in chronic kidney disease (CKD) was unclear. This study aims to investigate the relationship between Zonulin and systemic inflammation (SI), endothelial dysfunction (ED), especially renal functions, in patients with CKD. Materials and Methods: One hundred sixty-three participants were enrolled in this study. All participants were divided into two groups, patient and control groups, according to the presence of CKD (eGFR