After 12 weeks of rosiglitazone treatment, significant increases in total and small dense low-density lipoprotein, and the total: high-density lipoprotein (HDL)-cholesterol ratio were found. The large HDL concentration and HDL particle size decreased significantly with rosiglitazone compared with placebo. These data indicate the production of a more atherogenic lipid profile with rosiglitazone, a consideration when selecting treatment for the growing population of HIV-infected patients with type 2 diabetes and dyslipidemia.