Objectives The aim of this study is to explore different methods for screening and diagnosing hypertension—which definitions and criteria to use—in children and in addition to determine the prevalence of hypertension in Dutch overweight children.

Design A cross-sectional study performed in the Dutch Child Health Care setting.

Setting Four Child Health Care centres in different cities in the Netherlands.

Participants 969 overweight (including obese) and 438 non-overweight children, median age 11.7 years (range 4.1–17.10), 49% boys.

Main outcome measures The main outcome was blood pressure, and the difference in prevalence of hypertension using different criteria for blood pressure interpretation: using the first blood pressure measurement, the mean of two measurements and the lowest of three measurements on two different occasions.

Results Looking at the first measurement alone, 33% of overweight and 21% of non-overweight children had hypertension. By comparing the mean of the first two measurements with reference values, 28% of overweight children and 16% of non-overweight children had hypertension. Based on the lowest of three consecutive measurements, the prevalence decreased to 12% among overweight children and 5% among non-overweight children at visit one and at visit two 4% of overweight children still had hypertension.

Conclusions The prevalence of hypertension is highly dependent on the definitions and criteria used. We found a prevalence of 4% in overweight children, which is considerably lower than suggested by recent literature (4%–33%). This discrepancy can be explained by our more strict definition of hypertension. However, to draw any conclusions on the prevalence, normal values using the same definition of hypertension should be established. Despite the low prevalence, we recommend measuring blood pressure in all overweight children in view of later cardiovascular morbidity and mortality.