Omega-3 carboxylic acids (OM3-CA) reduce plasma total TG and apoCIII but raise LDL-C. Little is known about the effect of OM3-CA on lipoprotein subspecies. LDL that has apoCIII predicts CVD more strongly than LDL that does not have apoCIII. OM3-CA selectively increase the subspecies of LDL that does not contain apoCIII. OM3-CA does not increase LDL that has apoCIII.