WASHINGTON — White House visitor logs are public documents, a federal judge ruled today, rejecting a legal strategy the Bush administration had hoped would get around public records laws and let them keep their guests a secret.

The ruling is a blow to the Bush administration, which has fought the release of records showing visits by prominent religious conservatives.

Visitor records are created by the Secret Service, which is subject to the Freedom of Information Act. But the Bush administration has ordered the data turned over to the White House, where they are treated as presidential records outside the scope of the public records law.

But U.S. District Judge Royce C. Lamberth ruled logs from the White House and Vice President Dick Cheney's residence remain Secret Service documents and are subject to public records requests.

In a lawsuit brought by Citizens for Responsibility and Ethics in Washington, a liberal watchdog group, Lamberth ordered the Secret Service to turn over visitor logs regarding nine conservative religious commentators, including James Dobson, Gary Bauer and Jerry Falwell.

"I think it's hugely significant," said Anne L. Weismann, the watchdog group's chief counsel. "The judge saw their arguments for what they were."

White House spokesman Tony Fratto and Justice Department spokesman Charles Miller said lawyers were reviewing the decision and they would have no immediate response. The Bush administration is expected to appeal the ruling.