To assess the agreement between self-reported and parent-reported dietary and physical activity habits in children; and to evaluate the socio-economic determinants of healthier habits (Mediterranean diet and physical activity) among children.

Cross-sectional analysis of children recruited to a cluster-randomized controlled trial (Program SI!). Information about children’s and parents’ dietary and physical activity habits was obtained through validated questionnaires (Program SI! questionnaires, Kidmed, Krece Plus and Predimed scores).

Twenty-four schools in Madrid, Spain.

Children (n 2062) aged 3–5 years and their parents (n 1949).

There was positive agreement between parental- and self-reporting for three of the six children’s habits examined. Parents’ dietary and physical activity patterns were associated with those of their children. The main determinants of higher scores in children were higher parental age, the mother’s scores, Spanish origin and higher awareness of human health (P<0·005). Children from parents with a low educational level had lower odds for scoring positively on items such as using olive oil (OR=0·23; 95 % CI 0·13, 0·41) and not skipping breakfast (OR=0·36; 95 % CI 0·23, 0·55), but higher odds for meeting the recommendations for consuming pulses (OR=1·71; 95 % CI 1·14, 2·55). Other habits being influenced by parental socio-economic status included the consumption of vegetables, fish, nuts, avoidance of fast food, and consumption of bakery products for breakfast.

Children’s habits may be influenced by their parents’ health awareness and other socio-economic characteristics. These findings suggest that intervention strategies, even in very young children, should also target parents in order to achieve maximum success.