Aim: To identify the time required by children with cystic fibrosis (CF), diabetes or asthma to complete daily treatment tasks and the hassle they experienced when completing these tasks. To compare parent and child reports of daily treatment time and hassle. To investigate the relationship between treatment time and hassle, and (i) children's health-related quality of life (HRQL); and (ii) disease severity.Methods: 160 children aged 10-16 years with CF, type 1 diabetes, or asthma were followed over a 2-year period. Information about children's treatment time and hassle, and their HRQL was obtained from parents and children at baseline, 1-year and 2-year follow-up assessments.Results: On average, children with CF reported spending 74.6 +/- 57.0 min completing treatment tasks, children with diabetes spent 56.9 +/- 27.8 min and children with asthma spent 6.4 +/- 9.3 min. Parents reported that children spent less time that was reported by their children. Over the two years, parent and child reports describing treatment time for children with CF did not vary significantly (P = 0.3). Treatment time for children with diabetes increased (P = 0.02) whereas that for children with asthma reduced (P = 0.001). The level of hassle experienced by children when completing individual treatment tasks was low for all three conditions. There was no significant relationship between treatment time and children's HRQL.Conclusion: Children with CF or diabetes spent a substantial amount of time each day completing the treatment tasks. Although this was not related to HRQL, it could impact the ability to comply with complex and all home-based-therapies for some children.