The intentions of our investigation were (1) to search for atherogenic risk factors and signs of incipient atherosclerosis in children and adolescents with type 1 diabetes (T1DM) in comparison to well-matched control subjects, (2) to evaluate risk factor associations with carotid intima media thickness (cIMT) in diabetic patients and control subjects, and (3) to acquire a better knowledge of early atherogenesis in children and adolescents with and without T1DM. 94 diabetic children (age median 12.3 years, HbA(1c) median 7.7%) and 40 non-diabetic controls (age median 12.3 years) were investigated. Mean cIMT was determined using high-resolution B-mode ultrasound with an automated contour identification procedure. Compared to controls, subjects with diabetes had significantly elevated cIMT (p = 0.041) and systolic BP (p = 0.007) but showed a less atherogenic lipid profile. Most markers of inflammation, endothelial function and fibrinolytic activity were higher in diabetic subjects than in controls. Multiple linear regression analysis revealed a significant relationship (r = 0.53, p = 0.036) between bilateral mean cIMT and diverse risk factors in patients with T1DM. Spearman rank correlation showed that diabetes duration (rho = 0.32, p = 0.029), systolic BP (rho = 0.32, p = 0.004), weight (rho = 0.257, p = 0.022), and height (rho = 0.265, p = 0.018) significantly correlated with bilateral mean cIMT in the 94 diabetic patients. In conclusion, in well-controlled type 1 diabetic children systolic BP may be of greater importance than dyslipidaemia in early atherogenesis. BMI, markers of sustained inflammation, endothelial dysfunction and fibrinolytic activity are increased in diabetic versus non-diabetic children but none of them correlates significantly with cIMT. Their prognostic value remains to be determined.