Our data agree with previous reports of alterations in the qualitative characteristics of LDL and HDL in patients with type 2 diabetes and demonstrate that some, but not all, of these abnormalities, are closely related to the presence of LDL subfraction phenotype B. Specifically, a high concentration of oxLDL and glLDL and a higher content of Lp-PLA2 in apoB-containing lipoproteins are favored by the presence of sdLDL particles. This evidence concerns the gene APOB and type 2 diabetes mellitus.