The 1996 "Update on the 1987 Task Force Report on Blood Pressure in Children and Adolescents" adopted the fifth Korotkoff phase to define diastolic blood pressure and added height, in addition to age and gender, to develop new standards for blood pressure (BP) in children. The present study was performed to determine whether these changes altered the previously reported prevalence of hypertension in junior high school-aged children. Blood pressure screening was conducted in 19,452 fifth to eighth grade students. All students with a systolic blood pressure more than the 70th percentile had their BP measured a second time (rescreening). Using the 1996 criteria, systolic hypertension was found in 2.7% and diastolic hypertension in 2% after the screening. After the rescreening, systolic hypertension had fallen to 0.8% and diastolic hypertension to 0.4%. The prevalence of systolic hypertension was slightly higher and diastolic hypertension slightly lower than in 1987. These reports show that the overall prevalence of hypertension (1%) using the 1996 Updated Task Force criteria is similar to the prevalence using the original 1987 criteria. These results also confirm the importance of the Task Force recommendation that multiple BP measurements should be obtained before making a diagnosis of hypertension.