OBJECTIVES: To compare diabetes management in adults between England and the United States, particularly focusing on the impact of a universal access health insurance system. DESIGN: Analysis of the nationally-representative surveys Health Survey of England, 2003 (unweighted n =14 057) and the National Health and Nutrition Examination Survey, 2001-2002 (unweighted n =5411). SETTING AND PARTICIPANTS: Adults 20-64 years of age; individuals >65. MAIN OUTCOME MEASURES: Glycaemic, lipid and blood pressure control and medication use among individuals with previously diagnosed diabetes. RESULTS: Among those aged 20-64 the prevalence of diagnosed diabetes was lower in England (2.7%) than in the USA (5.0%). The proportion with diabetes receiving treatment was similar for the two countries. However, the mean HbA1c in England was 7.6%: in the USA it was 7.5% for those with insurance and 8.6% for those without insurance. The proportion of individuals on ACE inhibitors in England was 39%: in USA it was 39% for those with insurance, and 14% for those without. CONCLUSIONS: Individuals in a healthcare system providing universal access have better managed diabetes than those in a market based system once one accounts for insurance.