BACKGROUND The radial artery (RA) is used as an alternative conduit to the traditional saphenous vein bypass graft in some cardiac surgery centres. Despite limited clinical trial data, many centres appear to be using routine drug therapy to prevent spasm of the RA graft in the immediate and late postoperative period. OBJECTIVE To determine the proportion of patients in Canadian cardiac surgery centres having RA bypass grafts and the percentage of patients routinely receiving drug therapy to prevent spasm of these grafts. METHODS A questionnaire was sent to all cardiac surgery centres in Canada requesting data for the year 2000 on the total number of bypass surgery operations and the number of patients having RA bypass grafts. Information on approaches taken toward prophylaxis against spasm of RA grafts was also requested. RESULTS The use of RA grafts ranged between 1% and 50%. Twenty-five of 27 centres used antispasm prophylaxis with calcium channel blockers with or without long acting nitrates both in the intensive care unit and on the surgical ward. Calcium channel blockers were prescribed routinely in all 25 centres with 12 centres also using long acting nitrates. Only two centres routinely continued nitrates on the ward. The duration of antispasm therapy varied from several weeks up to six months. CONCLUSIONS Prophylaxis against spasm of RA grafts is practised in over 95% of Canadian surgical centres despite limited clinical outcome data to support this practice.