Peripheral arterial disease (PAD) is common in older people. An ankle-brachial index (ABI) < 0.9 can be used as an indicator of PAD. Patients with low ABI have increased mortality and a higher risk of serious cardiovascular morbidity. However, because 80% of the patients are asymptomatic, PAD remains unrecognised in a large group of patients. The aims of this study were 1) to examine the prevalence of reduced ABI in subjects aged 80 and over, 2) to determine the diagnostic accuracy of the medical history and clinical examination for reduced ABI and 3) to investigate the difference in functioning and physical activity between patients with and without reduced ABI.