The fourth amendment protects the right of citizens to be "secure in their persons, houses, papers, and effects" against unreasonable government intrusion. This protection extends to computers, which are effects, and to information processed and stored by computers, which can be categorized as papers. The U.S. constitution requires that a search for a computer and its papers be a reasonable search. "Reasonableness" is generally best established with a valid search warrant. Certain procedural requirements must be met for a valid warrant to be issued. There must be a showing of probable cause, supported by oath or affirmation; and the warrant must particularly describe the place to be searched and the persons or things to be seized. Since the probable- cause and particularity requirements pose unique problems when computers are involved, the article focuses on compliance in these areas. The execution of the search warrant is also discussed. Also explained are the requirements of the Privacy Protection Act of 1980, which provides special protection for documentary materials prepared or collected for dissemination to the public. In such cases, the statute requires the government to use a subpoena rather than a search warrant to acquire the materials. 55 notes