Critics questioned the timing of Mr. Bush's visit, which came six weeks after poor conditions and neglect of veterans were exposed there.
The news of neglected war veterans outraged Capitol Hill, caused resignations at the Pentagon, and generated promises of better treatment from the Bush administration.
The revelations of shoddy treatment at the Walter Reed Army Medical Center in Washington — considered one of the Army's premier facilities for treating those wounded in war — was an embarrassment to Mr. Bush, who routinely speaks of the need to support the troops.
The president toured the main hospital and Abrams Hall, where soldiers were transferred after they were removed from the facility's Building 18 — and where moldy walls, rodent infestation and other problems went unchecked until reported by the media. He said his conversations with those who had been in Building 18 left him "disturbed by their accounts."
"The problems at Walter Reed were caused by bureaucratic and administrative failures," the president told about 100 medical workers and patients at the hospital. "The system failed you and it failed our troops and we're going to fix it."
Among the areas of the hospital that Mr. Bush toured were a typical — but empty — patient room in Abrams Hall that featured a large wide-screen television and a Macintosh computer, and the physical therapy unit of the main hospital. Along the way, he presented awards to soldiers recovering from serious wounds suffered in Afghanistan and Iraq
"It is not right to have someone volunteer to wear the uniform and not get the best possible care," the president said at the end of his more than two-hour visit. "I apologize for what they went through and we're going to fix the problem."
"Walter Reed is not a photo-op," said Bobby Muller, president of Veterans for America. "Walter Reed is still broken. The DoD health care system is still broken. ... Our troops need their commander in chief to start working harder for them."
White House spokeswoman Dana Perino said "I would disagree with the characterization" that Mr. Bush is using Walter Reed as merely a picture-taking opportunity. She said it took some time to clear enough room on the president's schedule to spend more than three hours with patients and staff at Walter Reed, to find out from them what more needs to be done.
"He is going to spend ample time there to hear from them," Perino said. "He will talk about ... bureaucratic and administrative failures that need to be addressed."
Still, Mr. Bush's trip was cut short by about an hour.
The president said important steps, including the replacement of military leadership in charge of the hospital, have been taken already.
"We're not going to be satisfied until everyone gets the kind of care that their folks and families expect," Mr. Bush said.
The president, though, devoted much of his brief statement to praising the medical care veterans receive at Walter Reed.
"The soldiers and Marines stay here only for a few months, but the compassion they receive here stays with them for a lifetime," Bush said. "Americans must understand that the problems recently uncovered at Walter Reed were not the problems of medical care."
Mr. Bush has appointed a presidential commission to study the problems, and the Pentagon, Veterans Affairs Department and Congress are conducting a slew of reviews. But troops and veterans say many of the issues are well known and have long been in need of response.
Since the disclosures last month, three high-level Pentagon officials have been forced to step down.
This week, the House voted to create a coterie of case managers, advocates and counselors for injured troops. The bill also establishes a hotline for medical patients to report problems in their treatment.