Household and workplace exposure to environmental tobacco smoke (ETS) is associated with various deleterious health effects. We evaluated the health impact of ETS in Italy. We considered only those health conditions for which systematic quantitative reviews were available. We used relative risks from the reviews while data on the proportion of the Italian population exposed to ETS were derived from national statistics or from ad hoc studies. A total of 2.033 newborns per year are of low birth weight (< 2500 grams) in Italy (7.9%) because of maternal exposure to ETS during pregnancy. There are 87 sudden infant deaths (16.9%) due to post natal maternal active smoking. 21.3% of acute respiratory infections during the first two years of life are due to parental smoking (about 77.000 children); 27.000 cases of asthma (9.1%), 48.000 cases of chronic respiratory symptoms, 64.000 cases of middle ear effusions among children and adolescents are due to parental smoking exposure. The annual estimates of mortality from lung cancer and ischemic heart disease due to ETS exposure from the spouse are 221 and 1896, respectively. Workplace exposure is associated with 324 lung cancer deaths and 235 deaths from ischemic heart disease. Although these estimate are based on several assumptions and they have large uncertainties, the results underline the need and the urgency of public health measures to reduce ETS exposure in the household and in the workplaces in Italy.