This illness presents significant incidence and mortality, in all the regions of the world where the cigarette consumption persists. It enters the related causes of death to the tobacco we have: cancer of lung, larynx, esophagus, stomach, col of uterus and others, beyond cerebral vascular accidents, cardiovascular illnesses (THEY WENT and angina) and pulmonary illness obstrutiva chronicle (chronic bronchitis and enfisema). The tobacco is responsible for almost 90% of the cases of lung cancer. As estimative for the year of 2002 of the INCA (National Institute of the Cancer), it was responsible for 21.425 cases of cancer of lung and 15,955 deaths associates to these disgnostic (CANCER OF LUNG AND TOBACCOISM the NUMBERS SERGIO JAMNIK*/DOCTOR IN MEDICINE, OF DISCIPLINES OF PNEUMOLOGIA OF the UNIFESP/EPM) the lung cancer had abrupt increase from the consumption of the tobacco in the world. the tobaccoism is responsible for 90% of deaths for brnquico cancer reflects summons it association of this neoplasia with the tobacco. Ones of the constant concerns of the World-wide Organization of Greets is the determination of adjusted writs of prevention in the control of chronic-degenerative illnesses e, in special of the cancer. Until 4,720 had been today identified substantiate in 15 chemical functions in the smoke of the cigarette, of which more than 60 present cancergena activity. The main substances are the policclicos aromatical hydro-carbons that if they form for pirossntese or pirodecomposio for the high temperatures reached in the tip of the cigarette (950 1.050C); other substances as nitrosaminas volatile, amino aromatical, pireno, fluoranteno, catecol, rsenic, nickel, cadmium, acid, phenols, cresis, formolacetaldedos and polnio 210 also are identified as carcinognicas. 2,1 PASSIVE TOBACCOISM AND CANCER In the decade of 1980 had appeared some articles suggesting association enter mortality for lung cancer in passive smokers and the tobacco consumption in spouses. In a study it was proven that not smoking women had died for lung cancer, had its husbands to consume a considerable cigarette number (more than a mallet per day).