U.S. Patent and Trademark Office- Providing high quality and timely examination of patent and trademark applications, guiding domestic and international intellectual property policy, and delivering intellectual property information and education worldwide.

Google Patent Search- The power of Google applied to U.S. patents. offers many of the same search features as the USPTO site, but with an easier-to-use design and with the patents displayed as PDFs. The PDFs allow downloading or printing of the whole document. Create an account to best utilize the site. New as of late 2008, a patent database with an IP exchange portal. U.S. and European patents are promised; search options are still under development. Free patent search tool.