Adiponectin (ADPN) counteracts the inflammatory response of the endothelium, which plays an important role in the development of atherosclerosis in patients with chronic kidney disease (CKD). Data in children with CKD are scarce. We examined serum ADPN concentration in 90 children with various renal disorders: 28 with CKD on conservative treatment (CKD), 21 on regular dialysis treatment (D), and 41 after kidney transplantation (Tx); 27 age-matched healthy children served as controls (C). Body mass index (BMI), estimated glomerular filtration rate (eGFR), lipids, homocysteine, high sensitivity CRP (hsCRP), and systolic blood pressure (SBP) were also measured. Mean serum ADPN concentration was significantly higher in patients with CKD (27.3 μg/ml ±15.0), on D (34.2 μg/ml ±14.9), and after Tx (23.6 μg/ml ±9.5) compared with ADPN levels in C (13.5 μg/ml ±6.1) (p < 0.0001). Serum ADPN concentration was inversely related to BMI (p = 0.001) and SBP (p = 0.004). In the multiple linear regression analysis, only SBP remained independently associated with ADPN plasma levels. Data show that children with CKD have significantly higher serum ADPN, even after Tx. The protective antiarthrosclerotic effect of ADPN may be mediated by lower SBP, a finding that deserves further study.