"I look at that as, in a certain respect, as being a good thing because it means our testing is much better," he said at the White House.
The US has 1.5 million coronavirus cases and nearly 92,000 deaths, according to Johns Hopkins University.
In second place is Russia, with nearly 300,000 confirmed cases.
What did Trump say?
On Monday, Mr Trump was hosting his first cabinet meeting since the US outbreak began.
"By the way, you know when you say that we lead in cases, that's because we have more testing than anybody else," he told reporters.
"So when we have a lot of cases," he continued, "I don't look at that as a bad thing, I look at that as, in a certain respect, as being a good thing because it means our testing is much better."
He added: "So I view it as a badge of honour. Really, it's a badge of honour.
"It's a great tribute to the testing and all of the work that a lot of professionals have done."
According to the Centers for Disease Control, a federal agency, the US had conducted 12.6m coronavirus tests by Tuesday.