BACKGROUND: In Tunisia, where the epidemiological transition phenomenon is well established, there are no data available at the population level on the cardiovascular disease (CVD) risk profile for children, although it is well known that risk factor development takes place in childhood. METHODS: We report an epidemiological survey based on a representative sample of 1569 urban schoolchildren of Sousse in Tunisia to assess the following CVD risk factors: hypertension, hypercholesterolaemia and other lipid disorders, obesity and tobacco consumption. RESULTS: The main results showed that girls had significantly higher levels of body mass index (BMI), diastolic blood pressure (DBP), total cholesterol, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol than boys, who however had significantly higher levels of systolic blood pressure (SBP). Total cholesterol was significantly correlated to BMI and decreased with age. Obesity (BMI = 27) was found in 7.9% of the study population and was significantly higher for girls (9.7%) than for boys (6%): chi 2 = 9.02, DF = 2, P = 0.011. Overweight (BMI = 25) was also significantly higher for girls (16%) than for boys (11.1%): chi 2 = 8.21, DF = 1, P = 0.0041. Smoking habit concerned 7.6% of the study population; it was significantly higher for boys (14.7%) than for girls (1.1%): chi 2 = 103.4, DF = 1, P < 0.00001. CONCLUSION: This study showed to some extent that Tunisia's urban population of schoolchildren is exposed early to CVD risk factors and all should be done to avoid the worsening of this profile. These results will serve as a baseline for assessment of future trends in the risk factors studied.