Diabetes complications are common and almost triple the annual cost of managing diabetes. Microvascular complications are the major risk in type 1 diabetes, while macrovascular complications are the major cause of morbidity and mortality in type 2 diabetes. Control of hyperglycaemia (target HbA(1c) level < or = 7%) and hypertension (target blood pressure < or = 130/80 mmHg) prevents microvascular complications in both types of diabetes; a multifactorial approach, comprising behaviour modification and pharmacological therapy for all risk factors, reduces the development of micro- and macrovascular complications in type 2 diabetes. The benefit of treating dyslipidaemia is at least as great in the diabetic population as in the non-diabetic population. Angiotensin-converting enzyme inhibitors and low-dose aspirin are indicated in people with diabetes and other cardiovascular risk factors. Regular annual screening for diabetes complications allows treatable disease to be identified. Aggressive management of hyperglycaemia and other risk factors can prevent many complications