Populations with Amerindian or African heritages are the one with the highest prevalence of diabetes worldwide. A large percentage of these individuals survived famine. However, the survival effect has become detrimental to their descendents living in an environment of caloric surplus. In countries, like Mexico and Jamaica, in which diabetes is highly prevalent, the onset of the disease happens at earlier ages. Our objective is to summarize diabetes data from Mexico and Jamaica and to discuss the opportunities that can result from an interethnic study. On one hand, the prevalence of diabetes in Jamaica is 17.9% in the 15+ age group. Jamaican researchers have built a cohort of families with early onset type 2 diabetes. In this population, this form of the disease is unrelated to MODY genes. On the other hand, the prevalence of diabetes in adult Mexicans is 14.4%. The group in which the greater percentual changes have occurred is the adults who are below the age of 40. More than two thirds of the early onset cases studied have a body mass index that is >25 kg/m2 and the clinical characteristics of metabolic syndrome. A minority of them has mutations in the MODY genes. The joint study of Mexican and Jamaican cohorts of early onset type 2 diabetes cases will be useful to identify new genetic and environmental players in the pathogenesis of this entity.