The oath or declaration is a patent application formality complete with signatures from each inventor.

It certifies important facts concerning the inventorship of an application like who invented the claimed invention. In addition, within the oath or declaration the inventors must certify that they understand the contents of the application and that they know of their duty to disclose all the relevant information. In addition, within the oath or declaration, the inventors must identify the specification as their disclosure.

These documents must list out each inventor. Neither an oath or a declaration may be changed in any way, shape or form after it is signed and sent in to the PTO. If there is an error in the oath, a completely new oath will have to be sent in with brand new signatures.

The major difference between an oath and a declaration is that an oath is sworn to be true before a notary of the public. A declaration includes a warning indicating that the signed individual realizes willfully false statements are punishable by law. Either one is acceptable; the PTO just wants a record showing a complete list of the inventor(s) and that they swear to be in compliance with the rules and regulations of patent law.

Both an oath or a declaration must be signed for by the actual inventors only. The power of attorney may not sign in their place.

The applicant may be allowed to include a substitute statement explaining the inventor is deceased, legally incapacitated, cannot be found or reached, or under obligation to assign the invention but refuses to make the oath or declaration.

Provisional applications do not require an oath or a declaration while nonprovisional applications do.

For nonprovisional applications filed before September 16, 2102 the Office will issue a Notice to File Missing Parts if an applicant does not submit the oath or declaration within a specified time period (which is usually 2 months after the filing date).

For applications filed on or after September 16, 2012, the inventor's oath or declaration can be postponed until the application is otherwise in condition for allowance. In this instance, the application must include an application data sheet that lists each inventor. The oath or declaration will need to be submitted no later than the date that the issue fee is paid.