OBJECTIVE: To review the effects of lipid-lowering therapy on small-dense low-density lipoprotein cholesterol (sdLDL-C).DATA SOURCES: Literature was obtained from MEDLINE (1989–September 2004) and references of selected articles. Key search terms included small-dense LDL-C and lipid-lowering drug therapy.DATA SYNTHESIS: Statins, fibrates, and niacin have demonstrated favorable effects on sdLDL-C, especially among patients with mixed dyslipidemia or hypertriglyceridemia. These effects include a reduction of sdLDL-C and/or a shift to the larger, less atherogenic LDL-C.CONCLUSIONS: Data suggest that statins, fibrates, and niacin are effective at reducing concentrations of sdLDL-C and possibly normalizing LDL-C subclasses.