The 70 year-old Kudlow's condition is not immediately known.
Our Great Larry Kudlow, who has been working so hard on trade and the economy, has just suffered a heart attack. The president tweeted that Kudlow is now at Walter Reed Medical Center. Kudlow's wife, Judy Pond, told the Washington Post late Monday night that "he's doing fine".
For five years before his White House appointment in March, Kudlow hosted a show on CNBC on business and politics, and he's worked at the Federal Reserve Bank of NY.
"Here's the thing. He really kind of stabbed us in the back", Kudlow said on CNN Sunday.
At the White House, however, he was one of the most visible and vocal of advisers arguing that the president was simply trying to fix a broken global trade system in which the United States was not being treated fairly.
Mr. Kudlow is nominally in favour of free trade, but has backed Mr. Trump's nationalistic economic agenda, which has included steel and aluminium tariffs against Canada, Mexico and the European Union, as well as threats of further tariffs on autos.