We attempted to clarify the association between angiotensin-converting enzyme (ACE) gene polymorphism and the other predictive factors for macroangiopathy in children and adolescents with uncomplicated insulin-dependent diabetes mellitus (IDDM). Sixty-three patients were divided into 3 groups according to the ACE genotypes. The lipid profiles were evaluated according to ACE genotypes. The level of lipoprotein(a) (Lp(a)) in the II genotype was significantly lower than that in groups with the D allele. Lp(a) significantly correlated with apo B/apo A-I (p < 0.001, r = 0.63) and atherogenic index (AI = (total cholesterol - high-density lipoprotein cholesterol)/high-density lipoprotein cholesterol; p = 0. 004, r = 0.36). We suggest that the D allele may affect the level of Lp(a) and the other lipid profiles in IDDM.