This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.
While double patenting and prior art rejections may seem similar, there are key differences:
- Double patenting compares claims, while prior art rejections compare claims to disclosures
- Terminal disclaimers can overcome nonstatutory double patenting but not prior art rejections
- Double patenting requires some commonality in ownership or inventorship
- Prior art exceptions may not apply to double patenting rejections
As stated in MPEP 804: “Rejections over a patent or another copending application based on double patenting or under 35 U.S.C. 102 or 103 are similar in the sense that both require comparison of the claimed subject matter with at least part of the content of another patent or application, and both may require that an anticipation or obviousness analysis be made. However, there are significant differences between a rejection based on double patenting and one based on prior art under 35 U.S.C. 102 or 103.”