To compare levels of anxiety of children with chronic illness with healthy peers and population norms. Meta-analysis integrated results from 332 studies. Children with chronic illness had elevated levels of anxiety (d = 0.18 standard deviation units). Strongest elevations were found for chronic fatigue syndrome, migraine/tension headache, sensory impairment and epilepsy. Paediatricians should screen for anxiety symptoms in children at risk and offer interventions, if needed.