Leno asked Biden during a taping of "The Tonight Show" why the U.S. was sending 10 accused spies back to Russia while getting only four in return.
"That doesn't seem fair," Leno said.
"We got back four really good ones," Biden reassured Leno. "And the ten, they've been here a long time, but they hadn't done much."
Leno then showed a sultry photo of alleged Russian agent Anna Chapman and asked: "Are our spies this hot?"
Biden's reply, in a mock-serious tone: "Let me be clear. It was not my idea to send her back."
The vice president also said he had one more suggestion for the deal that was ignored.
"I thought they'd take Rush Limbaugh," he said.
The spy exchange on an airport tarmac in Vienna.
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Lawyer: Chapman Would Have Preferred to Stay
Biden opened the show in a comedy bit with Leno. It was his first appearance since taking office in January 2009.
Before becoming vice president, Biden had appeared on "Tonight" several times.
President Obama, first lady Michelle Obama and White House senior adviser David Axelrod also have made appearances on the late-night show.
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On Friday, Leno jabbed Biden for his tendency to make very public gaffes, pointing out an open-microphone expletive Biden uttered when Mr. Obama signed health care legislation in April.
Biden said he warned Mr. Obama before taking the job.
"I told the president two things when he asked me to do the job," Biden said. "I said, 'Just two conditions, Mr. President. I'm not going to wear any funny hats, and I'm not changing my brand.' And I kept my promise."
Biden went on to demonstrate that speaking style when Leno asked him who would win .
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"I've got the Netherlands, but what the hell do I know?" he said. "I thought LeBron was going to stay."