Background: Strict glycaemic control reduces risk of complications and improves quality of life in patients with type 1 diabetes mellitus. Real Time Continuous Glucose Monitoring System (RT-CGMS) is a novel system which can provide patients and health care professionals with real time information about the blood glucose level without the need for multiple invasive measurements. Furthermore, with continuous monitoring it is possible to identify trends in glycaemic profiles. Its effectiveness and safety have never been tested in a population of patients with type 1 diabetes mellitus treated with insulin through an implanted pump.