This is the "Patent Searching" page of the "Intellectual Property Law Research" guide.
Alternate Page for Screenreader Users
Skip to Page Navigation
Skip to Page Content

Intellectual Property Law Research  

Last Updated: Aug 23, 2017 URL: Print Guide RSS Updates

Patent Searching Print Page

Conducting a Patent Search

The first step in the process of applying for a patent is to search existing patents to make sure that the invention has not already been "discovered" by someone else.  This process is known as researching "prior art," and should be done before an inventor spends time, money and effort applying for a patent.


Massachusetts Institute of Technology (MIT) Libraries Video: Patents: An Introduction: Why Search for Patents? What is a Patent?

"Patents: An Introduction - Why Search for Patents? What is a Patent?" by Massachusetts Institute of Technology Libraries is licensed under CC BY 3.0 Unported.


Patent Classification

From the USTPO's Classification Resources 7 Step Strategy to Searching Patents:

  1. Brainstorm keywords related to the purpose, use and composition of the invention.
  2. Look up the words in the Index to the U.S. Patent Classification to find potential class/subclasses.
  3. Verify the relevancy of the class/subclasses by using the Classification Schedule in the Manual of Classification.
  4. Read the Classification Definitions to verify the scope of the subclasses and note "see also" references.   

Cooperative Patent Classification System (CPC): The USPTO began using the CPC system for published utility patents on January 1, 2013.


Patent Search Websites

United States Patent and Trademark Office (USPTO) (free):  database contains all US patents issued since 1790. Search the full-text of patents issued since 1976.  The full-text of the patent includes the claims made in the patent, descriptive information, and any images associated with the patent.  Older patents may be searched by patent number, issue date and classification. 

Quick Search

Advanced Search

Patent Number Search

Advanced Google Patent Search (free): issued patents from 1790, selected patent applications. Search by number, title, inventor, original assignee, classification, and full text.

Pat2PDF (free): patent search website (by number only) that will generate the PDF version of the patent. The website can do one patent or 20 patents. Each PDF is rendered as a link of the page.

Patent Lens (free): Worldwide, open-access, free full-text patent resource. Patent search interface in Chinese, English, Russian and French.

BloombergLaw (log in required): Intellectual Property > Specialized Searches > searchable database of patents, published applications and assignments.

WestlawNext (log in required): Intellectual Property > (right column) Patents ( > Search Patents, Applications and Assignments


Loading  Loading...