A cross-sectional stratified sample of 1249 adolescent secondary school boys was studied. More than 25% of boys did not practice any physical exercise. More than half of the parents (54.5%) were consanguineous. High prevalence of parental history of hypertension, diabetes and high blood lipids was found. Smoking amounted to 11.8%. The prevalence of obesity was 23.3%. The study showed that 6.8% had a high systolic blood pressure and 13.0% (162) had high diastolic blood pressure. There is a need for a national programme to prevent and control cardiovascular risk factors among adolescents.