Objective: Effects of pump treatment vs. four times daily injections were explored in children with diabetes with regard to quality of life and impact of disease as well as adverse effects and parameters of metabolic control. Methods: An open, parallel, randomized controlled prospective comparative study lasting 14months was completed by 38 type 1 children with diabetes (age 4-16yr) following a 3.5-months run-in phase. Standardized quality-of-life Pediatric Quality of life Inventory (PedsQL) and impact of disease scores were obtained every 3.5months as well as regular medical parameters. Parallel treatment group data and longitudinal within-patient data were analysed for each treatment modality. Results: Within-patient comparisons of the two treatment modalities showed significant improvement in PedsQL and impact scores after pump treatment. Treatment group comparisons did not show significant improvement. Pump treatment resulted in decreased symptomatic hypoglycaemia and lowered haemoglobin A1c by 0.22% after run in. Conclusions: Within-patient comparison suggests that metabolic control, frequency of severe hypoglycaemia (a threefold decrease), quality of life and impact of disease scores are improved by pump treatment in comparison to regular treatment with four daily insulin injections. © 2008 The Authors Journal compilation © 2008 Blackwell Munksgaard.