Aims: Continuous intraperitoneal insulin infusion (CIPII) is a last-resort treatment option for patients with type 1 diabetes mellitus (T1DM) who fail to reach adequate glycaemic control with subcutaneous (SC) insulin therapy. Aim was to compare the long-term effects of CIPII and SC insulin therapy among patients with T1DM in poor glycaemic control. Methods: Patients in which CIPII was initiated in 2006 were compared with a control group of T1DM patients who continued SC therapy. Linear mixed models were used to calculate differences between the baseline (2006) and final (2013) measurements within and between groups. Results: A total of 95 patients of which 21 were using CIPII and 74 using SC insulin were included. Within the CIPII group, the number of hypoglycaemic episodes decreased with -5 (95% CI -8 to -3) per 2 weeks while it remained stable among SC patients. Over time, only the number of hypoglycaemic episodes decreased more with CIPII as compared to SC insulin treatment (difference: -6 (95% CI -9 to -4)). There were no differences between treatment groups regarding clinical parameters and quality of life scores over time. Pump or catheter dysfunction led to ketoacidosis in 6 patients: 2 using CIPII and 4 SC insulin. Conclusions: After 7 years of follow-up, there is a persistent decline of hypoglycaemic events among CIPII treated T1DM patients. Besides less hypoglycaemic episodes with CIPII therapy, there are no differences between long-term CIPII and SC insulin therapy. (C) 2014 Elsevier Ireland Ltd. All rights reserved.