BACKGROUND AND AIMS:Childhood hypertension is a constantly increasing health problem. Data regarding its prevalence and particularly the prevalence of its phenotypes in the Greek population are limited; therefore, the aim of the study was to determine them in a large sample of Greek children. METHODS:A sample of 2655 schoolchildren (9-13 years) participated in the Healthy Growth Study, i.e. a cross-sectional epidemiologic study conducted in 77 primary schools in four large regions in Greece. This study shows results on 2571 children (1286 boys), for whom full data on systolic and diastolic blood pressure indices were available, as well as physical examination, anthropometric and physical activity data. RESULTS:The observed prevalence rates were: prehypertension, 14.2%; stage 1 hypertension, 15.7%; and stage 2 hypertension, 7.3%. Girls had substantially higher hypertension prevalence than boys (25.3% vs. 20.8%). The prevalence rates for prehypertension and stage 2 hypertension were higher in younger than older children (22.4 vs. 13.7% and 8.6 vs. 7.5% respectively), while stage 1 hypertension was higher in children >12 years old compared to younger children (14.9 vs. 12.1%). Isolated systolic hypertension (ISH) was the most prevalent phenotype (11.9%). Moreover, presence of hypertension was positively associated with body mass index (BMI) and waist circumference in both genders, and with sedentary behaviors only in boys. CONCLUSIONS:The prevalence of hypertension in Greek children and adolescents is alarming and among the highest reported in European countries, while the differences between genders in hypertension phenotype prevalence also provide valuable insight on this problem. The present data may guide future public health initiatives to tackle childhood hypertension in Greece.