By definition, brittle diabetes (BD) is an unstable condition. Patients with BD suffer chronically from poor metabolic control, characterized by severe instability of glycemic values with frequent and unpredictable hypoglycemic and/or diabetic ketoacidosis episodes that cannot be attributed to failure in management. Quality of life is dramatically compromised because of very frequent acute complications leading to hospital admissions and because of premature chronic complications. It remains difficult to identify all patients with BD as diagnostic criteria are still not well defined. In practice, metabolic instability is manifested most obviously by chaotic glycemic profiles, which show greater and more unpredictable variation than in "stable" patients with diabetes. It is important that patients with BD are not adequately controlled, even by closely supervised, intensive insulin regimens, including continuous subcutaneous and/or intravenous insulin infusion. Their care is often very expensive in terms of time and resources, and their lives are constantly at risk for severe metabolic derangement. Management can also be frustrating and demoralizing for everyone involved, including the patient's family as well as the diabetes care team. Adopting a team approach, involving a broad range of disciplines, is essential in treating patients with BD and helping them to achieve and maintain both normoglycemia and quality of life.