Treatment with continuous subcutaneous insulin infusion (CSII) allows a large degree of treatment individualization and intensification in children with diabetes. The study's aim was to evaluate the impact of treatment with CSII on glycated haemoglobin level (HbA1c) in children with diabetes and investigate whether introduction of CSII is associated with an increased risk of acute complications of diabetes. Patients treated throughout the recruitment period exclusively with multiple daily injections (MDI) were matched for duration of diabetes and HbA1c level at baseline with patients treated exclusively with CSII in a 1:1 group ratio (n = 223 and 231 for MDI and CSII, respectively). The CSII group showed lower HbA1c after the observation period (7.98 ± 1.38 vs. 7.56 ± 0.97; P = 0.002). HbA1c variability measured as standard deviations of average values was also lower in the CSII group (0.73 ± 0.45 vs. 0.84 ± 0.54; P = 0.049). The rate of hospitalization due to acute events was similar in both groups (14.7/100 vs. 14.0/100 person/years in the MDI and CSII group, P = 0.72). Duration of hospital stay per year was on average 1.25 days shorter in the CSII group (P = 0.0004), but the risk of acute complications resulting in hospitalization did not differ between the groups (hazard ratio (HR) 1.16; 95% confidence interval (95% CI) 0.68-1.63). The most significant risk factor for hospitalization due to acute complications was baseline HbA1c concentration (HR 1.25; 95% CI 1.14-1.37). In conclusion, CSII treatment may improve glycemic control and reduce its variability. Change of MDI to CSII does not alter the risk of hospitalization and may reduce the annual duration of hospitalization in children with diabetes.