Background: The projected rising prevalence of diabetes and impaired fasting glucose (IFG) in developing countries warrants careful monitoring. The aim of this study was to present the results of the Costa Rican National Cardiovascular Risk Factors Surveillance System, which provides the first national estimates of diabetes and IFG prevalence among adults in Costa Rica. Methods: A cross-sectional survey of 3653 non-institutionalized adults aged ≥20 years (87.8% response rate) following the World Health Organization STEPwise approach was built on a probabilistic sample of the non-institutionalized population during 2010. Known diabetes was defined as self-reported diagnosis, the use of insulin, or hypoglycemic oral treatment as consequence of diabetes during at least the previous 2 weeks before the survey. Unknown diabetes was defined no self-reported diabetes but with venous blood concentrations of fasting glucose >125 mg/dL determined by laboratory testing. Impaired fasting glucose was defined as fasting glucose between 100 and 125 mg/dL among those without diabetes. The prevalence of diabetes and IFG prevalence was estimated according gender, body mass index (BMI), waist circumference (WC), educational level, and physical activity level. Results: Overall diabetes prevalence was 10.8% (9.5% known and 1.3% unknown diabetes) and IFG prevalence as 16.5%. The prevalence of known diabetes was higher among women >65 years compared with men of the same age group. Both known and unknown diabetes were significantly associated with higher BMI, increased WC, and low education level (P= 0.01). Conclusions: The prevalence of diabetes and IFG in Costa Rica is comparable to that in developed countries and indicates an urgent need for effective preventive interventions.