MPEP § 805 — Effect of Improper Joinder in Patent (Annotated Rules)

§805 Effect of Improper Joinder in Patent

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 805, including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Effect of Improper Joinder in Patent

This section addresses Effect of Improper Joinder in Patent. Primary authority: 35 U.S.C. 121. Contains: 1 prohibition and 1 permission.

Key Rules

Topic

Restriction Requirement (MPEP 802-803)

2 rules
StatutoryProhibitedAlways
[mpep-805-bb3a5a62277cf335761b13d7]
Patent Validity Not Questioned for Improper Joinder
Note:
A patent's validity cannot be challenged due to the failure of the Director to require restriction to a single invention.

35 U.S.C. 121, last sentence, provides “the validity of a patent shall not be questioned for failure of the Director to require the application to be restricted to one invention.” In other words, under this statute, no patent can be held invalid for improper joinder of inventions claimed therein.

Jump to MPEP SourceRestriction Requirement (MPEP 802-803)Restriction and Election Practice (MPEP Chapter 800)
StatutoryPermittedAlways
[mpep-805-be689fee949dd656131e6812]
Patent Validity Not Questioned for Improper Joinder of Inventions
Note:
A patent cannot be invalidated due to improper joinder of inventions claimed in the application.

35 U.S.C. 121, last sentence, provides “the validity of a patent shall not be questioned for failure of the Director to require the application to be restricted to one invention.” In other words, under this statute, no patent can be held invalid for improper joinder of inventions claimed therein.

Jump to MPEP SourceRestriction Requirement (MPEP 802-803)Restriction and Election Practice (MPEP Chapter 800)

Citations

Primary topicCitation
Restriction Requirement (MPEP 802-803)35 U.S.C. § 121

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31