The present study shows associations between parental smoking and respiratory diseases in Italian children and adolescents participating in SIDRIA-2. We studied associations (odds ratios, ORs, and 95% confidence intervals, 95% CI) between exposure to mothers smoking fathers smoking, both parents' smoking, and three categories of cases: current asthma, current asthmatic symptoms, chronic bronchitis. At least one parent smoker was associated with a greater risk for asthmatic diseases compared to subjects not exposed. Our findings are in agreement with other published studies' results on the adverse effect of passive smoking on childhood respiratory health. The proportion of families with at least one parent smoker is very high (about 50%), confirming that measures aimed to reduce passive smoking in the community, and particularly in all places where children are present, are urgently needed in Italy.