This study examined the relationships of baseline phenotypes and the common polymorphisms in DGAT1 and DGAT2 with the lipid responses to niacin.Lipid responses in Chinese patients with dyslipidemia treated with the extended release (ER) niacin/laropiprant combination 1000/20 mg for 4 weeks and then 2000/40 mg for 8 weeks (n = 121, the primary study) or with ER niacin 1500 mg for at least 4 weeks (n = 68, the replication study) were analyzed according to genotypes of DGAT1 rs7003945 T>C and DGAT2 rs3060 T>C polymorphisms.Treatment with ER niacin improved all lipid parameters in both studies.