OBJECTIVE To evaluate the accuracy of home blood glucose meters during hypoglycemia. METHODS Six blood glucose meters—One Touch II (LifeScan, Milpitas, CA), Companion II (Medisense, Cambridge, U.K.), Reflolux (Boehringer Mannheim, Mannheim, Germany), Accutrend (Boehringer Mannheim), Elite (Bayer, Munich, Germany), and HemoCue (HemoCue, Ängelholm, Sweden)—were compared with a reference method (Beckman Glucose Analyzer 2). Glucose concentrations from arterialized venous blood samples were measured using all glucose meters (whole blood) and the reference method (plasma) during hypoglycemic-hyperinsulinemic clamps in 15 subjects. RESULTS In total, 663 blood glucose monitor readings and 119 reference values ranging from 2.28 to 3.89 mmol/l were analyzed. The correlation coefficients and the percentage of measurements within 20% and outside 40% of the reference values for each glucose meter were as follows: One Touch II: 0.91, 99.2% and 0%; Companion II: 0.81, 88.2% and 2.5%; Reflolux: 0.78, 85.0% and 0.9%; Accutrend: 0.88, 46.0% and 6.6%; Elite: 0.78, 75.6% and 4.2%; and HemoCue: 0.93, 96.6% and 0% (P < 0.001). CONCLUSIONS There were substantial differences between the blood glucose meters during hypoglycemia, and none of the devices met the latest criteria recommended by the American Diabetes Association.