To examine the extent to which Canadian residents seek medical care across the border, we collected data about Canadians' use of services from ambulatory care facilities and hospitals located in Michigan, New York State, and Washington State during 1994-1998. We also collected information from several Canadian sources, including the 1996 National Population Health Survey, the provincial Ministries of Health, and the Canadian Life and Health Insurance Association. Results from these sources do not support the widespread perception that Canadian residents seek care extensively in the United States. Indeed, the numbers found are so small as to be barely detectible relative to the use of care by Canadians at home.