The importance of measuring blood pressure routinely in children over 3 years, and in specific circumstances in younger children, is increasingly recognized. The incidence of pediatric hypertension is relatively high, its prevalence increasing, and high blood pressure tends to track into adulthood. Interpretation of a blood pressure measurement requires knowledge of sex-, age-, and height-specific normative values. Blood pressure is classified as normal if < 90th percentile, and high if > 95th percentile, and as prehypertension if 90-95th percentile. The methods available to measure blood pressure together with their advantages and disadvantages, as well as pitfalls in measurement, are discussed. Also discussed is Ambulatory Blood Pressure Monitoring which may define if there is "dipping", i.e. a decrease in blood pressure by > 10% during sleep, a novel parameter that may help identify children at risk of sustained hypertension or its complications. Signs, symptoms and physical findings of the child with hypertension are reviewed.