"The existing licenses will be revoked".
The aerospace giant had said the Iran contracts would support tens of thousands of jobs.
Among U.S. companies, plane maker Boeing has signed the biggest deals, and U.S. Treasury Secretary Steven Mnuchin said Tuesday that its existing licenses - as well as those of its European competitor, Airbus Group - would be invalidated.
Boeing was supposed to supply Iran Air for 80 aircraft at a list price of about $17 billion through 2025.
The company separately has a 30-airplane deal with Iran's Aseman Airlines, the Post reports. No deliveries have been made yet.
Boeing said it would consult with the government on what comes next.
In a statement immediately after Trump's announcement, Boeing said it "will consult with the US government on next steps". Over 19.6 billion dollars 110 aircraft were to be purchased from Boeing.
Boeing shares closed up 1.8 percent Wednesday to $344.50.
Airbus, based in Toulouse, France, is subject to US export restrictions because more than 10 percent of its jet parts originate with USA companies such as United Technologies, Rockwell Collins and General Electric.
Key buyers of Iranian crude in Europe are still assessing the impact of the return of U.S. sanctions against Iran, with rival Iraqi and Saudi producers said to be in prime position to eat into Iran's European market share.
European planemaker Airbus said on Tuesday before the Mnuchin news conference that it would study Trump's decision, adding that it would take some time. "That is why Iran came to the table".
He said there might be some exclusions, but he did not elaborate.
The French and British foreign ministers have both said their governments will seek to protect their companies' business interests in Iran and even boost trade.
Not only will US companies be affected by the change in policy, but the president said at the White House that under certain circumstances the USA will impose sanctions on other countries that continue to deal with Iran.
Mnuchin did not spell out what the administration would consider as a "significant reduction" in purchases of oil.
The original Iran nuclear deal had paved the way for the country to emerge from years of economic isolation and sanctions. It remains unclear how much those nations will comply, if at all.
Smith said it was unclear whether Trump would actually impose sanctions on European Union companies that continue to deal with Iran, adding that the threat may be strategic, and that the administration could eventually end up granting exemptions. He did not say which countries, but Saudi Arabia has the greatest spare production capacity.
Finally, it throws another spanner into the works of a global oil market in which steady demand and reduced spare capacity had already left prices at $75 a barrel.