Continuous subcutaneous insulin infusion (CSII) with a portable insulin pump has been used for several years in the treatment of adult patients with diabetes mellitus (DM). This treatment, however, has rarely been utilised in children and adolescents. We studied the use of CSII in 16 children and adolescents with type 1 DM at Tampere and Kuopio University Hospitals between 1992 and 1997. The longest treatment periods are more than 4 years. The reasons for switching to CSII treatment and the goals achieved were evaluated. Glycaemic control before and during CSII treatment and the occurrence of hypoglycaemia and ketoacidosis were analysed. Compared with conventional insulin treatment, improved glycaemic control and a reduced frequency of hypoglycaemic events were achieved with CSII in those with particularly poor initial metabolic control (HbA1c >10.0%). The overall satisfaction with pump therapy was high in both patients and their families. According to our experience, CSII may be of benefit, especially in young infants with type 1 DM, but also in affected adolescents with unacceptable glycaemic control.