AbstractObjective:To investigate the influence of parental physical activity on offspring’s nutritional status in the 1993 Pelotas (Brazil) birth cohort.Design:Birth cohort study.Setting:The main outcomes were overweight and obesity status of children. The main exposure was parental physical activity over time, measured during the 11, 15 and 18 years of age follow-ups. The exposure was operationalised as cumulative, and the most recent measure before the birth of child. We adjusted Poisson regression models with robust variance to evaluate crude and adjusted associations between parental physical activity and offspring’s nutritional status. All analyses were stratified according to the sex of the parent.Participants:A total of 874 members from the 1993 Pelotas (Brazil) birth cohort followed-up at 22 years of age with their first-born child were analysed.Results:Children were, on average, 3·1 years old. Crude analyses showed that the mother’s cumulative physical activity measure had an indirect association with the prevalence of children’s obesity. The most recent maternal physical activity measure before the birth of the child was associated with 41 % lower prevalence of obesity in children, even after adjustment for confounders.Conclusions:The most recent maternal physical activity measure was indirectly associated with the prevalence of obesity in children. No associations were found for fathers, reinforcing the hypothesis of a biological effect of maternal physical activity on offspring’s nutritional status.