US Patent Office All US patents since 1790! Full text provided, which includes citations, references, abstract and the text of the patent. References to other patents are linked. Images for all patents available, in TIFF format which must be printed one page at a time.
PattoPDF: all USPTO patents free, converted to PDF, and printable.
Free Patents Online: Free website, offering PDF versions of all patents from number 4000000-.
World Intellectual Property Organization, PCT WO patents with citations, abstracts and references supplied. WO applications since 1997- also included.
European Patent Office. Patent applications in original language from EP and WO may be found here. JP applications with English title and abstract are available. Images from PCT, EP and JP are available.
Crazy Patents: a site to make you laugh and wonder in amazement at the crazy things people patent.