Background: The prevalence of obesity is increasing worldwide. Obesity in children and adults leads to diabetes mellitus type 2 and cardiovascular disease. Aim: To determine the prevalence of high blood pressure in overweight and obese children in the Caribbean. Methods: In a cross-sectional study, weight and height were measured in all 5-16-year-old children attending public school in 2008 on Bonaire, an island in the Caribbean. Cut-off values for body mass index (BMI) are defined by the International Obesity Task Force. Blood pressure was measured in all overweight and obese children as well as in a control group with normal weight and compared with reference values from the National High Blood Pressure Working Group on Children. Results: 94% (2023/2152) of all children participated in the study. 17% (335/2023) of the children were overweight (excluding obesity) and a further 12% (246/2023) were obese. Hypertension was found in 13% (67/526) of children of normal weight, in 23% (71/307) of overweight children and in 53% (127/242) of obese children. Compared with normal-weight children, the odds for hypertension were 2.1 (95% CI 1.4-3.0) for overweight children and 7.2 (95% CI 5.0-10.3) for obese children. Conclusion: There is a high prevalence of hypertension in overweight and obese children on Bonaire. As hypertension is a harbinger of cardiovascular disease, early detection and treatment of overweight and obese children is of paramount importance and their blood pressure needs to be measured regularly. © W. S. Maney & Son Ltd 2012.