Type 1 diabetes is a generally accepted atherogenic risk factor, and diabetic patients who smoke markedly accelerate the atherosclerotic process. The main intentions of our investigation were to ascertain differences between juvenile active/passive smokers and non-smokers with type 1 diabetes regarding the number and spectrum of cardiovascular risk factors and their associations with smoking. Ninety-two patients were enrolled comprising 19 active/passive smokers (median age 15.9 years) and 73 non-smokers (median age 12.3 years). To determine age-dependent influences we compared age- and gender-matched groups of 12 smokers with 12 non-smokers. Smokers had significantly higher HbA1c, fructosamine, total cholesterol, LDL cholesterol, apolipoprotein B, serum P-selectin, and lower serum L-selectin than non-smokers. However, L-selectin levels were not different between the age-matched smoker and non-smoker groups. A significant positive relation (Spearman rank correlation) was found between smoking and age, HbAlc, fructosamine, total cholesterol, apolipoprotein B, and P-selectin; a negative relationship between smoking and L-selectin. We conclude that smoking in children and adolescents with type 1 diabetes increases the cardiovascular risk through the deterioration of glucose metabolism, lipid profile, and endothelial function. Therefore, smoking diabetic juveniles may increase their number of cardiovascular risk factors from 1, diabetes, by another four factors, i.e. smoking, hyperglycemia, dyslipidemia, and endothelial perturbation.