We studied 1,274 healthy children of both sexes from 10 until 18 years of age, in Fuenlabrada, Madrid. We knew the tobacco consumption by means of direct asking to the children, without the presence of their parents. We studied the smoking habit of their parents by means of inquiries. The percentage of smoker children was 30% (24% of them had smoker parents, and 6% did not). We studied the tobacco influence in several parameters of cardiovascular risk; it was found that C-HDL levels in the smoker children were 5 mg/dl lower than the non-smokers, and the ratio C-LDL/C-HDL in the smokers was 1,2 times greater than in the non-smokers.