A longtime member of Bush's inner circle, Rove was nicknamed "the architect" by the president for designing the strategy that twice won him the White House.

A criminal investigation put Rove under scrutiny for months during the investigation into the leak of a CIA operative's name but he was never charged with any crime.

Bush was expected to make a statement Monday with Rove.

"Obviously it's a big loss to us," White House deputy press secretary Dana Perino said. "He's a great colleague, a good friend, and a brilliant mind. He will be greatly missed, but we know he wouldn't be going if he wasn't sure this was the right time to be giving more to his family, his wife Darby and their son. He will continue to be one of the president's greatest friends."

Since Democrats won control of Congress in November, some top administration officials have announced their resignations. Among those who have left are White House counselor Dan Bartlett, budget director Rob Portman, chief White House attorney Harriet Miers, political director Sara Taylor, deputy national security adviser J.D. Crouch and Meghan O'Sullivan, another deputy national security adviser who worked on Iraq. Defense Secretary Donald Rumsfeld was forced out immediately after the election as the unpopular war in Iraq dragged on.

Rove is expected to write a book after he leaves. He disclosed his departure in an interview with The Wall Street Journal.

"I just think it's time," Rove said in an interview at this home on Saturday. He first floated the idea of leaving to Bush a year ago, the newspaper said, and friends confirmed he'd been talking about it even earlier. However, he said he didn't want to depart right after the Democrats regained control of Congress and then got drawn into policy battles over the Iraq war and immigration.

"There's always something that can keep you here, and as much as I'd like to be here, I've got to do this for the sake of my family," said Rove, who has been in the White House since Bush took office in 2001.

Rove's son attends college in San Antonio and he said he and his wife plan to spend much of their time at their nearby home in Ingram.

Rove, currently the deputy White House chief of staff, has been the president's political guru for years and worked with Bush since he first ran for governor of Texas in 1993.

In the interview, Rove predicted Bush will regain his popularity, which has sunk to record lows because of the war in Iraq.

Rove also predicted conditions in Iraq would improve and that the Democrats would nominate Hillary Rodham Clinton for president, calling her "a tough, tenacious, fatally flawed candidate."

Rove testified before a federal grand jury in the investigation into the leak of the name of Valerie Plame, a CIA officer whose husband was a critic of the war in Iraq. That investigation led to the conviction of I. Lewis "Scooter" Libby on charges of lying and obstructing justice. Plame contends the White House was trying to discredit her husband.

Attorneys for Libby told jurors at the onset of his trial that Libby was the victim of a conspiracy to protect Rove. Details of any save-Rove conspiracy were promised but never materialized.

The most explicit testimony on Rove came from columnist Robert Novak, who outed Plame in a July 2003 column. He testified that Rove, a frequent source, was one of two officials who told him about Plame. Libby, with whom he seldom spoke, was not a source.

The jury did not hear testimony that Rove was not indicted after testifying five times before the grand jury, occasionally correcting misstatements he made in his earlier testimony.

Nor did the jury hear testimony about how Rove is credited as an architect of Republican political victories and has been accused by opponents of playing dirty tricks.