Background: The objective of the present study was firstly to collect data on smoking in adolescents from a high cardiovascular risk population and, secondly, to analyse the association between smoking and other cardiovascular risk factors. Methods: A cross-sectional study was conducted in 1,526 adolescents (12–17 years) in 24 secondary schools of the Belgian province of Luxembourg. Data collection included smoking, physical activity habits, blood pressure, total cholesterol, anthropometry, diet (e.g. alcohol consumption) and oral contraceptive use. Results: The prevalences of current and occasional smokers were 14.8 and 5.4% respectively, with similar proportions in both genders. The proportion of smokers was significantly higher in the technical course than in the classical one (35.6 versus 24% in the 15–17 years age group). In the 15–17 year old group, regular smokers consumed significantly more free sugar, alcohol, coffee and soft drinks and male smokers ate less fruit and vegetable than non-smokers. In the same age group, 32.6% of female smokers were oral contraceptive users versus 17.9% in the non-smokers group. Other cardiovascular risk factors were similar in regular smokers and non-smokers. Conclusion: Adolescent smoking is a cause for concern in this sample from a high cardiovascular risk population. Few links were found between the prior and other cardiovascular risk factors. However, the high prevalence of smoking in the technical course and its combined usage with oral contraceptives in teenagers deserve careful attention.