The DPP-4 inhibitors (DPP4I) are widely used in many countries but there are relatively few data on ethnic differences in their pharmacology and efficacy. Although there do not appear to be race-specific differences in the pharmacokinetic properties of DPP-4I in published studies, there is some evidence that race is associated with glycaemic response to DPP-4I especially in the case of Asians. In one meta-analysis published in 2013, there was a mean 0.26% (2 mmol/mol) lower HbA1c when ≥ 50% of participants were Asian compared with studies involving < 50% Asian subjects, an effect that has also been found in more recent studies with fewer Asian patients [9, 15]. However, aggregated rather than individual patient data were used in the meta-analysis which also did not differentiate between the South and East Asians despite the greater insulin resistance in the latter group. In a recent analysis of data from the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS), the mean 4-month placebo-adjusted HbA1c reduction was greatest in East Asians in comparison with other racial groups including the two largest groups, White Caucasians and Other (mainly South) Asians, during a period in which use of other blood glucose-lowering medications was kept stable. The greater glycaemic response in the East Asians might reflect relatively greater beta cell function and/or greater carbohydrate consumption which is a potent stimulus for intestinal incretin release. The data supporting these mechanisms will be discussed.