© 2015 Llauradó et al This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective To investigate the usefulness of Fibroblast Growth Factor 23 (FGF-23) and vitamin D as possible biomarkers of pre-clinical atherosclerosis, assessed as arterial stiffness (AS), in a group of subjects with type 1 diabetes (T1DM) and no previous cardiovascular events. Research Design and Methods 68 T1DM patients and 68 age- and sex-matched controls were evaluated for 1) age, sex, diabetes duration, physical activity, smoking, alcohol intake, BMI, blood pressure, fasting plasma glucose, HbA1c, estimated glomerular filtration rate (eGFR) and lipid profile; 2) microvascular complications; 3) blood concentrations of FGF-23 and mineral metabolism parameters (calcium, phosphate, parathyroid hormone (PTH) and 25-hydroxy-vitamin D (25 (OH)D)); 4) AS, assessed as aortic pulse wave velocity (aPWV); and 5) low-grade inflammation (hsCRP, IL-6, sTNFaR1, sTNFaR2) and endothelial dysfunction (ED) markers (ICAM-1, VCAM-1, E-Selectin). Results Patients with T1DM had higher aPWV compared with controls (P<0.001), but they did not present differences in 25(OH)D (70.3(50.4-86.2)nmol/L vs. 70.7(59.7-83.0)nmol/L; p = 0.462) and in FGF-23 plasma concentrations (70.1(38.4-151.9)RU/mL vs. 77.6(51.8-113.9) RU/mL; p = 0.329). In T1DM patients, higher concentrations of FGF-23 were positively associated with aPWV after adjusting for eGFR and classical cardiovascular risk factors (model 1: ß = 0.202, p = 0.026), other mineral metabolism parameters (model 2: ß = 0.214, p = 0.015), microvascular complications, low-grade inflammation and ED markers (model 3: ß = 0.170, p = 0.045). Lower 25(OH)D concentrations were also associated with higher aPWV after adjusting for all the above-mentioned factors (model 3: ß = -0.241, p = 0.015). Conclusions We conclude that both FGF-23 plasma concentrations (positively) and 25(OH)D serum concentrations (negatively) are associated with AS in patients with T1DM and no previous cardiovascular events.