Boston Scientific says the IRS is trying to collect half-a-billion dollars in back taxes related to the company's 2006 acquisition of Guidant Corp.
The company says it has received "notices of deficiency" from the IRS claiming a tax bill of $525 million plus interest.
The dispute concerns internal pricing of transactions between domestic and foreign operations.
Boston Scientific representatives say it disagrees with the IRS analysis and will fight the agency in Tax Court.
Boston Scientific has major operations in Minnesota.