OBJECTIVES: Since the implementation of Pediatric Regulations/Legislations in the USA (Pediatric Research Equity Act - PREA) and in Europe (Pediatric Investigation Plans - PIPs), product development programs should include pediatric studies. The objective of this study is to review opinions (EMA) and requirements (FDA) given by both agencies in the case of sitagliptin (alone and combined) for the treatment of diabetes mellitus in children. METHODS: The EMA and FDA websites were explored to: (1) Identify the products marketed under the INN of sitagliptin (alone or in combination), and (2) Identify the associated PIPs or PREA requirements. The search was performed on January 18, 2013. RESULTS: Eight products were marketed in Europe [i.e., sitagliptin (Januvia, Ristaben, Tesavel, Xelvia) and sitagliptin + metformin (Janumet, Efficib, Ristfor, Velmetia)]. Four products were authorized in the USA [i.e., sitagliptin (Januvia); sitagliptin + metformin (Janumet, Janumet XR); sitagliptin + simvastatin (Juvisync)]. The FDA and the EMA provided the same opinion for sitagliptin alone, i.e., deferred pediatric study for patients aged 11 to 16. The FDA and the EMA disagreed on sitagliptin + metformin. The EMA granted a waiver for all subsets of the pediatric population on the grounds that the specific medicinal product does not represent a significant therapeutic benefit over existing treatments, while the FDA required a pediatric study under PREA for the treatment of type 2 diabetes in pediatric patients aged 11 to 16. As for sitagliptin + simvastatin, the FDA grants a waiver on the grounds that the product does not represent a meaningful therapeutic benefit over existing therapies for pediatric patients. CONCLUSIONS: The FDA and the EMA have similar opinions except for the combination sitagliptin + metformin. One reason could be the higher prevalence of type 2 diabetes mellitus in children in the USA as compared to Europe.