Diabetes outcomes provide a rudimentary but useful lens by which to analyse the performance of a primary care system. Care co-ordination, continuity of care and well informed patients - the key functions of a primary care system - can make a substantial difference to the potential for hospital admissions related to diabetes. Korea’s poor outcomes in hospitalisations relative to its population prevalence for diabetes suggests shortfalls in the quality of care delivered for diabetes in Korea, and in particular, the quality of primary care.