This paper reports the results of a postal questionnaire survey of Directors of Public Health in all health authorities in the United Kingdom (as at March 1994). Our aim was to examine variations in the purchasing of coronary artery bypass grafting, percutaneous transluminal coronary angioplasty and coronary angiography. Information on planned service developments in cardiology was also sought. The response rate was 62%. The mean rate of CABG was 374 per million total population (range 162-710); PTCA 183 (range: 18-648); and coronary angiography 1,010 (range 581-2,334). The mean ratio of invasive treatment to angiography was 1:2 Variations in provision were not related to mortality from coronary heart disease or the availability of a local provider. Those districts purchasing higher levels of CABG tended to purchase higher levels of PTCA (Spearman's r = 0.52). Observed variations in purchasing of invasive treatments and investigation for coronary heart disease do not relate to population "need' as defined by mortality rates from CHD. The greatest variations are seen in the purchasing of PTCA, an intervention whose place in the management of CHD is as yet not fully defined. Consensus guidelines on the appropriate use of these interventions and on population needs are required.