Introduction:
Second-hand smoke (SHS) can cause cancer, increasing the risk of heart and respiratory diseases in children and adults. In Spain, since 2011 private areas (cars) are the main places of exposure. Object Describe the characteristics associated to SHS exposure at home in a population less than 15 years in Catalonia.

Methods:
Between 2012 and 2016, 3,831 minors were included in the Health Survey of Catalonia (ESCA). The percentage of SHS exposure (number of people who smoke at home) is calculated according to sociodemographic characteristics and their association is analysed.

Results:
17.7% of minors were exposed. Significant differences are observed according to age (18.9% in group 4-14 years versus 14.0% in group 0-3); according to social class (20.5% in low class versus 10.9% in upper class); father’s educational level (21.9% with primary education/no education versus 9.2% with university studies) and mother’s educational level (20.8% with lower levels versus 10.3% with university studies).

Conclusions:
Almost one out of five minors is exposed to SHS at home, especially in families with lower social class or educational level. It is important to move forward in the protection of children in environments that are still not regulated, proposing a new regulatory framework and strengthening information and health education in family environment.