['To assess the impact of a disease management programme for patients with diabetes mellitus (Type 1 and Type 2) on cost-effectiveness, quality of life and patient self-management. By organizing care in accordance with the principles of disease management, it is aimed to increase quality of care within existing budgets.', 'Single-group, pre-post design with 2-year follow-up in 473 patients.', 'Substantial significant improvements in glycaemic control, health-related quality of life (HRQL) and patient self-management were found. No significant changes were detected in total costs of care. The probability that the disease management programme is cost-effective compared with usual care amounts to 74%, expressed in an average saving of 117 per additional life year at 5% improved HRQL.'] Is a disease management programme for patients with diabetes mellitus associated with improved quality of care within existing budgets?