How can I find out if my invention is already patented?

Public users may perform preliminary searches of patent information in a variety of formats including on-line, microfilm, and print at the United States Patent and Trademark Office (USPTO) Public Search Facility located in Alexandria, VA.

State of the art computer workstations provide automated searching of patents issued from 1790 to the current week of issue. Full document text may be searched on U.S. patents issued since 1971 and OCR text from 1920 to 1970. U.S. patent images from 1790 to the present may be retrieved for viewing or printing. Some foreign patent documents are available.

A complete patent backfile in numeric sequence is available on microfilm or in optical disc format. Official Gazettes, Annual Indexes (of Inventors), the Manual of Classification and its subject matter index, and other search aids are available in various formats.

Patent assignment records e Biz of transactions affecting the ownership of patents, microfilmed deeds, and indexes are also available.

The Public Search Facility is located in the Madison East building on the first floor at 600 Dulany St., Alexandria, VA 22313. The telephone number is 571-272-3275.

Users can access the full-text searchable database containing patent information for all U.S. patents granted since 1976 and all patent application publications (first published in March 2001), on the USPTO web site at e Biz.

You may retain a patent attorney or agent to conduct a complete search. For information on registered patent attorneys and agents in your area, you may visit the Office of Enrollment and Discipline web site at

Inventors can also perform a preliminary search of patents at one of the Patent and Trademark Depository Libraries (PTDLs) established throughout the United States. These libraries have copies of patents in microfilm and/or optical disc format arranged in numerical order. They have classification search tools, automated search aids, and photocopy facilities available to the public. For information on your nearest PTDL, you may visit PTDL web site at


>> see also How to Search

USPTO FAQ - Questions and Answers (04OCT2004)