Unless vetoed by President Barack Obama or blocked by a federal appeals court, the independent ruling would bar the importation of AT&T variants of the iPhone 4, 3GS and 3G, as well as the original iPad and iPad 2 which run on the second-largest American mobile network.
The latest Apple products, including the iPhone 5 and the fourth-generation of the iPad, are not affected.
The ITC's decision against Apple was largely unexpected, particularly because it reverses an earlier ruling that found Apple’s products were not infringing on Samsung’s patents.
The ITC said its ruling was “final” and that it had terminated its investigation, but Apple could appeal against the decision to a higher authority.
"We are disappointed that the Commission has overturned an earlier ruling and we plan to appeal. Today's decision has no impact on the availability of Apple products in the United States," Apple spokeswoman Kristin Huguet said in a statement.
Once close business partners, Samsung and Apple have become increasingly intense rivals, and the case is the latest amid a flurry of litigation between the two electronics giants, who are locked in legal battles in no less than 10 countries.
In a separate patent fight in a U.S. federal court last year, Samsung was ordered to pay Apple more than $1 billion for patent infringement, an award that was later slashed to $598.9 million.
Tuesday's ruling raises the incentives for the two sides to reach a more comprehensive settlement but both sides have offered no hint at a settlement.
Samsung said in a statement that the ITC decision "confirmed Apple's history of free-riding on Samsung's technological innovations."
"Our decades of research and development in mobile technologies will continue and we will continue to offer innovative products to consumers in the United States," it said.
Lyle Vander Schaaf, an intellectual property lawyer at Brinks Hofer Gilson & Lione, told the Wall Street Journal that it is rare for federal appeals courts to delay exclusion orders during appeals and presidential vetoes are even rarer.