The objective of this study was to examine whether there are international variations in the use of evidence-based medical therapy in patients undergoing percutaneous coronary revascularization. We analyzed the medical therapy of patients in the United States (US) (n = 878), Europe (n = 134), and Canada (n = 274) who underwent percutaneous coronary revascularization in either the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT-I) (enrollment from August 1991 to April 1992) or the Canadian Coronary Atherectomy Trial (CCAT) (enrollment from July 1991 to August 1992). We found that at the time of hospital admission, Canadian patients had the highest rates of treatment with aspirin (95% vs 57% US and 78% Europe; p = 0.002), calcium antagonists (75% vs 48% US and 43% Europe; p 0.0001), beta blockers (60% vs 32% US and 46% Europe; p = 0.02), and combination anti-ischemic therapy (67% vs 43% US and 56% Europe; p = 0.0001). By discharge, however, Canadian patients had the lowest rates of treatment with nitrates (12% vs 40% US and 44% Europe; p = 0.0001) and combination anti-ischemic therapy (29% vs 53% US and 47% Europe; p < 0.01). At both admission and discharge, rates of treatment with angiotensin-converting enzyme inhibitors and lipid-lowering agents were < 15% in all 3 regions. We conclude that significant international variations exist in the use of evidence-based medical therapy in patients undergoing percutaneous coronary revascularization.