Although no reason was given, Snow recently told conservative radio talk show host Hugh Hewitt that, due to financial reasons, he did not expect to remain on the White House staff through the remainder of President Bush's term.

Bush told reporters Friday that he will "sadly accept" Snow's resignation.

Flanked by Snow and Perino in the White House press room, the president spoke warmly of his departing press secretary.

"It's been a joy to watch him spar with you," Bush told reporters.

Bush said he was certain of two things in regard to Snow.

"He'll battle cancer and win," Bush said, "and he'll be a solid contributor to society."

Turning to Snow, the president then said: "I love you, and I wish you all the best."

Taking the podium, Snow said he was thankful for the opportunity to serve as press secretary.

"This job has been a dream for me -- and a blast," Snow said.

Snow's cancer was diagnosed for the first time in February 2005. His colon was removed, and after six months of treatment, doctors said the cancer was in remission.

Perino announced March 27 that Snow's cancer had recurred, and that doctors had removed a growth from his abdomen the day before.

Sources told CNN two weeks ago that Snow was planning to leave his job, possibly as early as September.

Snow, who had said he would leave his post before the end of Bush's second term, repeated that the decision is based on finances, not health. He took a major pay cut after leaving the world of cable television and talk radio to come to the White House.

According to The Washington Post, Snow makes $168,000 as the White House spokesman.

Bush tapped Snow to replace Scott McClellan in April 2006. Snow had been an anchor for "Fox News Sunday" and a political analyst for the Fox News Channel, which he joined in 1996. He also hosted "The Tony Snow Show" on Fox News Radio.

On Thursday, Snow told CNN his health is improving, citing two new medical tests this month which found the cancer has not spread.

"The tumors are stable -- they are not growing," Snow said of the results from an MRI and a CAT Scan. "And there are no new growths. The health is good."

The press secretary, whose hair has turned gray during chemotherapy treatment, said his black hair is expected to grow back in about a month.

"I'm also putting on weight again," he said after returning from a 10-day vacation. "I actually feel very good about" the health situation.

Snow said that on Friday he was to see his oncologist, and they will decide on some minor forms of chemotherapy to start as maintenance treatment.