Objective: To evaluate adiponectin levels in children and adolescents with type I diabetes, and their relationship to long term complications. Design: Cross sectional. Setting: Tertiary referral hospital, Cairo, Egypt. Participants: Thirty children and adolescents with type I diabetes mellitus, classified into complicated and non-complicated-and compared to 10 healthy age and sex matched subjects as a control group. Methods: All children underwent anthropometric measurements, neurological assessment, fundus examination, echocardiography and assays of HbA1c, creatinine, 24-hr urinary protein, and serumn adiponectin. Main outcome measure: Relationship of serum adiponectin to complications of type I diabetes mellitus, and glucose control. Results: Serum adiponectin was significantly elevated in complicated diabetes (10.3 +/- 5.9 pg/dL) as compared to the controls (6.5 +/- 3.7 pg/dL) (P<0.01), and correlated directly with HbA(1c) (P<0.05) and creatinine (P<0.001). Patients with nephropathy showed high values of adiponectin (15.7 +/- 3.7 pg/dL). Conclusion: Elevated adiponectin level in children and adolescents with type I diabetes indicates poor glycemic control and development of complications, especially nephropathy.