Terminal Disclaimer & Double Patenting

A Terminal Disclaimer is a type of limit on a patent. If an inventor has an invention he or she has a patent for, the inventor might make small changes to the invention and file a patent for the same invention with these changes. If the United States Patent and Trademark Office (USPTO) gives a second patent to the inventor, the second patent will have a terminal disclaimer attached. This terminal disclaimer is filed to overcome an obvious-type Double Patenting (ODP) rejection issued by the USPTO.

The terminal disclaimer means the second patent expires when the first patent does. It also means the inventor can only enforce the second patent if he or she owns both patents. If the inventor sells the first patent, he or she can’t enforce the second one.