Epidemiological evidence suggests that obesity and depression are highly co-morbid. In a national cohort study, we examined whether parents caring for children with disabilities were more likely to be classified as obese compared to parents of children without disabilities and if obesity was associated with depressive symptoms or child behaviour characteristics. Using data from the Growing Up in Ireland National Longitudinal Study of Children (2006 to date), 627 parents of children with developmental disabilities were compared with 7941 parents of typically developing children on objectively measured levels of obesity (body mass index ≥30kg/m(2)), depression, health behaviours, chronic health conditions, socio-demographic and child behavioural characteristics. Parents of children with disabilities were more likely to be classified as obese compared to control parents (24.5% vs. 19.6%, p=0.005, Cramer's V