Objective. To present the incidence and prevalence of diabetes mellitus in the Americas as found through a thorough review of published information on the subject. Methods. Data were obtained through a comprehensive review using the MEDLINE and BIREME bibliographical databases. In addition, government publications, conference reports, and meeting documents were identified by contacting government and nongovernmental organizations and other institutions. Incidence and prevalence rates were adjusted by age and sex, when possible, by the direct method using the world Segi population as the standard. The 95% confidence intervals were calculated using the Poisson distribution or the normal distribution. Results. Diabetes mellitus represents a major public health problem in the Americas, and there is evidence that its prevalence is increasing in some countries. Conclusions. Given that most Latin American and Caribbean nations are experiencing a demographic transition, it is expected that the prevalence of diabetes will continue to increase rapidly in the near future. Despite the economic constraints faced by the countries of the Americas, there is a clear need for more efforts in the area of diabetes prevention and control.