The bill is one of several in Congress that address the topic, a reflection of growing election-year discontent with rising drug prices.
The White House and Republican leaders in Congress have raised safety concerns in opposing allowing Americans to fill their prescriptions in Canada, where prices are lower by a third or more on many brand-name drugs.
The legislation introduced Wednesday is backed by Republican Sens. John McCain of Arizona, Trent Lott of Mississippi and Olympia Snowe of Maine. Democratic sponsors include Senate Democratic Leader Tom Daschle of South Dakota, Edward Kennedy of Massachusetts and Byron Dorgan of North Dakota.
Lott and Kennedy have opposed earlier efforts to legalize drug imports without certification from federal health officials that it can be done safely, as current law requires.
The bill would require the Food and Drug Administration to inspect U.S. importers and foreign exporters, a step that proponents say would address safety concerns.
It would eventually allow prescriptions to be filled in 20 countries, mainly in Europe. U.S. pharmacies and drug wholesalers that want to import medicines would have to register with the Food and Drug Administration as part of the safety program.
Only FDA-approved medicines manufactured at plants inspected by the FDA could be imported.
The pharmaceutical industry has staunchly opposed efforts to make drug imports legal. A coalition of health care groups with ties to the industry criticized the legislation, saying it would lead to a rise in counterfeit drugs in this country.