Conducting a Patent Search

diagram of an early airplane Diagram for a "flying machine" patented by O. and W. Wright on May 22, 1906 (patent #821,393).

The United States Patent and Trademark Officeexternal link (USPTO) web site allows you to search for patents and published patent applications.  The full-text of patents from 1976 to the present is searchable.  Patents from 1790 to 1975 are searchable only by current U.S. classification number, patent number or issue date.  The full-text of published patent applications since March 15, 2001 is searchable.

The USPTO advises that the most comprehensive patentability search of U.S. patents will be a search conducted by current U.S. classification number in their patent database.

The USPTO web site also contains various tools that will help you conduct a preliminary patentability search:

As a Patent and Trademark Depository Library, the New York State Library also provides access to the USPTO’s PubWEST and Cassis 2 search systems.  These time-saving tools can help you perform a more thorough patent search and are not available on the Internet.

The New York State Library has trained staff who will assist you in learning to use these tools.  Appointments are not required to use the collection but are recommended if you would like assistance in using these tools.  Appointments can be made by calling 518-474-5355 or by e-mail. The staff are not, however, patent attorneys or registered agents, and cannot provide legal advice, interpret your search results or strategies, or provide opinions on the viability of a patent application. A directory of attorneys and agentsexternal link registered to practice before the USPTO can be found on the USPTO web site. 

Other online search tools:

  • Esp@cenetexternal link – the European Patent Office's free search engine for international patents.  Includes over 70 countries, coverage varies from country to country.  One of the features for US patents is inventor name and patent title searching from 1920 to present.
  • Google Patent Searchexternal link – provides optical character recognition searching of scanned US patent images from 1790 to recent.
Last Updated: March 17, 2014