Up to one-third of patients with heart disease have diabetes. Cardiological status should be considered when deciding on treatment for diabetes. Patients with stable coronary disease can be treated with metformin, sulphonylureas or pioglitazone. Following an acute coronary syndrome, intensive insulin therapy with multi-dose insulin has been shown to reduce mortality, and longerterm treatment with pioglitazone may reduce recurrent events. There is little trial information for glycaemia control in patients with chronic heart failure, and metformin and insulin are both frequently used. Dipeptidylpeptidase-4 (DPP-4) inhibitors are new oral antidiabetic drugs, which are weight neutral, and the injected glucagon-like peptide-1 (GLP-1) receptor agonists reduce weight. Long-term outcome studies are awaited to see if they have cardiovascular advantages in any particular group of patients.