Introduction. The exposure to environmental tobacco smoke is a public health problem because of its potential risks for children. Objective. To determine the preventive actions taken by parents and/or caregivers of infants, toddlers, and preschoolers regarding environmental tobacco smoke exposure. Methods. Cross-sectional, analytical study in parents and caregivers of infants, toddlers, and preschoolers from Valdivia, Chile. A questionnaire on preventive measures regarding environmental tobacco smoke was administered. The questionnaire was analyzed with descriptive and association statistics using Fisher's exact test and logistic regression to calculate the odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) as an estimation of the risk for not taking preventive measures at home. Results. A total of 469 parents and caregivers participated. The prevalence of households with one member who smoked was 51.8%. Most of them smoked outside the house (92.2%). The most common measure taken outside the household was to avoid places where people smoked. In this setting, a significant difference was observed between men and women in relation to avoiding exposure (7.6% versus 2.2%; p= 0.040). A higher risk for not avoiding tobacco use inside or outside the housewas confirmed when a household member smoked (OR: 3.55; 95% CI: 2.05-6.14). Also, a lower risk was observed when there were two or more children in the household (OR: 0.46; 95% CI: 0.26-0.83). Conclusions. Most parents and caregivers ask others to smoke outside and avoid places where people smoke; however, the level of prevention is lower among households with smokers.