High levels of fibroblast growth factor 23 (FGF 23) are associated with mortality and cardiovascular events in patients with chronic kidney disease (CKD). Carotid intima-media thickness (CIMT) is a useful marker of subclinical atherosclerosis. This study aimed to investigate the relationship between serum FGF23 levels and CIMT of CKD patients. In this cross-sectional study, CIMT was measured in 162 patients with CKD Stage of 2-5 (age range 18-79 years, 61.7% males). Serum FGF23 levels were determined by enzyme-linked immunosorbent assay. CIMT was measured by ultrasonography. Serum FGF-23 levels were significantly higher (P = 0.046) in advanced CKD patients. CIMT was thicker in patients with advanced CKD patients (P = 0.01). CIMT was correlated with age (r = 0.486, P <0.001), smoking (r = 0.411, P <0.001), and 25-OH Vitamin D (r = -0.195, P = 0.045). There was no correlation between serum FGF23 and CIMT. Multivariate analysis showed that age (beta = 0.373, P <0.001), smoking (beta = 0.228, P = 0.004), and serum 25-hydroxyvitamin D levels (beta = -0.164, P = 0.042) were associated with CIMT. There was no relationship between FGF23 and CIMT. The CIMT was found to be related to increased age, smoking, and 25-hydroxyvitamin D in CKD patients.