Aims: To evaluate the effects of continuous intraperitoneal insulin infusion (CIPII) using implantable pumps on glycaemic control and duration of hospital stay in poorly controlled 'brittle' Dutch diabetes patients, and to assess their current quality of life. Methods: Thirty-three patients were included. Glycaemic control was retrospectively assessed with HbA1c levels acquired before implantation, 1 year later and at long-term follow up of 58 months. Duration of hospital stay the year before and the year following first implantation was extracted from hospital records. Determinants of long-term glycaemic response were sought. Self-report questionnaires were administered at 58 months follow-up only, to assess current psychopathology and quality of life. Results: Mean HbA1c decreased from 10.0 ± 2.3% to 9.0 ± 1.8% (P = 0.039) 1 year after implantation and stabilized at 9.0 ± 1.6% (P = 0.023) during long-term follow-up. Median number of hospital days in the 20 patients suffering from hospital admission before implantation decreased from 45 the year before implantation to 13 the year after (P = 0.005). Patients with a higher baseline HbA1c showed a larger long-term response (P ≤ 0.001). Relatively low levels for quality of life were found, as well as a higher than expected number of patients with psychiatric symptoms. Conclusions: CIPII proved effective in complex patients with a history of poor control and hospital admission. Despite a substantial long-term improvement in glycaemic control and diminished hospital stay, normal levels of glycaemic control and quality of life were not attained.