The aim of our study was to determine how often asthma control is achieved in children and adolescents, and how asthma affects parents' and children's daily lives.Interviews, including the childhood asthma control test (C-ACT), were conducted with 1,284 parents of asthmatic children (aged 4–15 yrs), as well as with the children themselves (aged 8–15 yrs; n=943), in Canada, Greece, Hungary, the Netherlands, South Africa and the UK.Parents reported mild asthma attacks at least weekly in 11% of children, and serious attacks (requiring oral corticosteroids or hospitalisation) at least annually in 35%. Although 73% of parents described their child's asthma as mild or intermittent, 40% of children/adolescents had C-ACT scores ?19, indicating inadequate control, and only 14.7% achieved complete Global Initiative for Asthma (GINA)-defined control and just 9.2% achieved Scottish Intercollegiate Guidelines Network (SIGN)/British Thoracic Society (BTS)-defined control. Guideline-defined asthma control was significantly less common than well-controlled asthma using the C-ACT (p<0.001). Asthma restricted the child's activities in 39% of families and caused lifestyle changes in 70%.Complete asthma control is uncommon in children worldwide. Guideline-defined control measures appear to be more stringent than those defined by C-ACT or families. Overall, parents underestimate their child's asthma severity and overestimate asthma control. This is a major potential barrier to successful asthma treatment in children.