Intermittent claudication has been studied in cardiovascular surveys but limited information is available on asymptomatic peripheral arterial disease. The purpose of this paper is to describe the prevalence of both asymptomatic and symptomatic disease and relation to ischaemic heart disease in the Edinburgh Artery Study. A cross-sectional survey was conducted on an age-stratified sample of men and women aged 55 to 74 years selected from age-sex registers in ten general practices in the city. Arterial disease was assessed in 1592 participants by means of the WHO questionnaire on intermittent claudication and measurement of the ankle brachial systolic pressure index (ABPI) and change in ankle systolic pressure during reactive hyperaemia. The prevalence of intermittent claudication was 4.5% (95% confidence interval (CI): 3.5%-5.5%). Major asymptomatic disease causing a significant impairment of blood flow occurred in 8.0% (95% CI: 6.6%-9.4%). A further 16.6% (95% CI: 14.6%-18.5%) had criteria considered abnormal in clinical practice: 9.0% had ABPI less than 0.9 and 7.6% had reactive hyperaemia pressure reduction greater than 20%. Intermittent claudication was equally common in both sexes. The ABPI and reactive hyperaemia results suggested a slight preponderance of asymptomatic disease in males and were consistent with an increasing prevalence with age and lower social class. Mean ABPI was higher in normal men than women, and was lower in the left leg than the right suggesting a unilateral predisposition to disease. Subjects with major asymptomatic disease had more evidence of ischaemic heart disease than in the normal population (relative risk (RR) 1.6; 95% CI: 1.3-1.9).(ABSTRACT TRUNCATED AT 250 WORDS)