The report by the 19-member Senate Judiciary Committee will be made public next month, but the Times obtained a draft copy on Tuesday.
It focuses on errors in the case of Zacarias Moussaoui, the only person accused directly in the hijacked-airliner attacks of Sept. 11. But it also points to a broader FBI culture that allowed the mistakes, the newspaper reported.
When Minnesota agents arrested Moussaoui last summer, they believed he was a terrorist who might use a commercial airplane as a weapon, so agents tried to obtain a search warrant under the 1978 foreign Intelligence Surveillance Act.
FBI officials in Washington denied the request, apparently unaware that the federal act clearly permitted a warrant in that case, the report said.
When agents searched Moussaoui's computer after Sept. 11 they found information on commercial airplanes, crop dusting and a telephone number for a suspected al Qaeda member in Germany, officials said.
Also, an agent in Phoenix, Arizona, informed bureau supervisors in Washington of a threat from an unusual number of young Arab men seeking flight training in the United States.
Sen. Arlen Specter, a Republican member of the committee and an author of the report, called the intelligence by field agents a "veritable blueprint of 9/11," the Times said.
The FBI had not seen the report and had no comment.