objective: to identify blood pressure values and estimate the frequency of risk factors for hypertension among middle school students. methods: this was a descriptive, cross sectional study, conducted in schools in the southeastern region of brazil. the sample consisted of 184 adolescents enrolled in the second semester of middle school, in 2009. in addition to the measurement of clinical variables, instruments were applied to identify risk factors associated with hypertension. results: an alteration in blood pressure was a parameter detected in 22.3% of the sample. among the risk factors investigated, family history of cardiovascular disease and alcohol consumption were the most prevalent. conclusion: there is need to enhance the measures of primary prevention and early detection of arterial hypertension among adolescents, with special attention to the assessment of family history and adoption of risk habits.