Aim: To compare the adherence to clinical guidelines by GPs as registered and glycaemic control in Turkish and Dutch type 2 diabetes patients. Design: A retrospective cohort study. Search of general practice medical records for diabetes-related variables of Turkish and Dutch diabetes patients, stratified for age and gender. Setting: Seventeen general practices (37 GPs) in the inner city of Rotterdam. Subjects: 196 type 2 diabetes patients (106 Turkish and 90 Dutch), known with diabetes for at least 18 months, were followed for two years during the 1992–1997 period. Main outcome measures: 1) Level of care as registered in the medical records based on eight quantifiable criteria derived from the national guidelines for GPs; and 2) glycaemic control (fasting and non-fasting blood glucose levels). Results: Turkish patients visited the GP for periodic control more often than Dutch patients. The other seven criteria were followed in an equal number of Turkish and Dutch patients. Turkish patients had a higher mean non-fasting plasma glucose level (12.9 mmol/l) than Dutch patients (10.8) (p=0.001) during the two-year follow-up. Conclusions: Although adherence to clinical guidelines as registered in Turkish and Dutch type 2 diabetes patients is comparable, Turkish patients have higher mean non-fasting plasma glucose level than their Dutch counterparts.