MPEP § 823 — MPEP § 823
Current through: 2022-07-01

823-Unity of Invention Under the Patent Cooperation Treaty 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Manual of Patent Examining Procedure 

 Chapter 0800 

 Section 823 
 

 
 
 
 
 
 823 Unity of Invention Under the Patent Cooperation Treaty [R-07.2015]

 The analysis used to determine whether the Office may require restriction
 differs in national stage applications submitted under 35 U.S.C. 371 (unity of invention
 analysis) as compared to national applications filed under 35 U.S.C.
 111(a) (independent and distinct analysis). See MPEP Chapter 1800 , in
 particular MPEP §
 1850 , § 1875 , and § 1893.03(d) , for a
 detailed discussion of unity of invention under the Patent Cooperation Treaty (PCT).
 However, the guidance set forth in this chapter with regard to other substantive and
 procedural matters (e.g., double patenting rejections ( MPEP § 804 ), election and
 reply by applicant ( MPEP §
 818 ), and rejoinder of nonelected inventions
 ( MPEP §
 821.04 ) generally applies to national stage applications
 submitted under 35 U.S.C.
 371 .
 

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 801-Introduction 

 802-Basis for Restriction Practice in Statute and Rules 
 802.01-Meaning of “Independent” and “Distinct” 

 802.02-Definition of Restriction 

 
 

 803-Restriction — When Proper 
 803.01-Review by Examiner with at Least Partial Signatory Authority 

 803.02-Election of Species Requirements – Markush Claims 

 803.03-Transitional Applications 
 803.03(a)-Transitional Application — Linking Claim Allowable 

 803.03(b)-Transitional Application — Generic Claim Allowable 

 
 

 803.04-Nucleotide Sequences 

 803.05-Reissue Application Practice 

 
 

 804-Definition of Double Patenting 
 804.01-Prohibition of Nonstatutory Double Patenting Rejections Under 35 U.S.C. 121 

 804.02-Avoiding a Double Patenting Rejection 

 804.03-Commonly Owned Inventions of Different Inventive Entities; Non-Commonly Owned Inventions Subject to a Joint Research Agreement 

 804.04-Submission to Technology Center Director 

 804.05-Impact of Patent Term Extension under 35 U.S.C. 156 on Nonstatutory Double Patenting 

 
 

 805-Effect of Improper Joinder in Patent 

 806-Determination of Distinctness or Independence of Claimed Inventions 
 806.01-Compare Claimed Subject Matter 

 806.02-[Reserved] 

 806.03-Single Embodiment, Claims Defining Same Essential Features 

 806.04-Genus and/or Species Inventions 
 806.04(a)-[Reserved] 

 806.04(b)-Species May Be Independent or Related Inventions 

 806.04(c)-[Reserved] 

 806.04(d)-Definition of a Generic Claim 

 806.04(e)-Claims Limited to Species 

 806.04(f)-Restriction Between Mutually Exclusive Species 

 806.04(g)-[Reserved] 

 806.04(h)-Species Must Be Patentably Distinct From Each Other 

 806.04(i)-Generic Claims Presented In a Separate Application After Issuance of Species Claims 

 
 

 806.05-Related Inventions 
 806.05(a)-Combination and Subcombination 

 806.05(b)-[Reserved] 

 806.05(c)-Criteria of Distinctness Between Combination and Subcombination 

 806.05(d)-Subcombinations Usable Together 

 806.05(e)-Process and Apparatus for Its Practice 

 806.05(f)-Process of Making and Product Made 

 806.05(g)-Apparatus and Product Made 

 806.05(h)-Product and Process of Using 

 806.05(i)-Product, Process of Making, and Process of Using 

 806.05(j)-Related Products; Related Processes 

 
 

 806.06-Independent Inventions 

 
 

 807-Patentability Report Practice Has No Effect on Restriction Practice 

 808-Reasons for Insisting Upon Restriction 
 808.01-Reasons for Holding of Independence or Distinctness 
 808.01(a)-Species 

 
 

 808.02-Establishing Burden 

 
 

 809-Linking Claims 
 809.01-[Reserved] 

 809.02-Election of Species Required 
 809.02(a)-Election of Species Required 

 
 

 809.03-Restriction Between Linked Inventions 

 
 

 810-Action on the Merits 

 811-Time for Making Requirement 
 811.01-[Reserved] 

 811.02-New Requirement After Compliance With Preceding Requirement 

 811.03-Repeating After Withdrawal Proper 

 811.04-Proper Even Though Grouped Together in Parent Application 

 
 

 812-Who Should Make the Requirement 
 812.01-Telephone Restriction Practice 

 
 

 813-[Reserved] 

 814-Indicate Exactly How Application Is To Be Restricted 

 815-Make Requirement Complete 

 816-[Reserved] 

 817-Outline of Letter for Restriction Requirement 

 818-Election and Reply 
 818.01-Election in Reply to a Restriction Requirement: Express 
 818.01(a)-Reply Must be Complete 

 818.01(b)-Election is Required, Even When Requirement Is Traversed 

 818.01(c)-Traverse is Required To Preserve Right of Petition 

 818.01(d)-Traverse of Restriction Requirement With Linking Claims 

 
 

 818.02-Election Other Than Express 
 818.02(a)-Election By Originally Presented Claims 

 818.02(b)-Generic Claims Only — No Election of Species; Linking Claims Only – No Election of Invention 

 818.02(c)-Election By Optional Cancelation of Claims 

 818.02(d)-Election By Cancelation of Claims, Lacking Express Election Statement 

 
 

 
 

 819-Office Generally Does Not Permit Shift 

 820-[Reserved] 

 821-Treatment of Claims Held To Be Drawn to Nonelected Inventions 
 821.01-After Election With Traverse 

 821.02-After Election Without Traverse 

 821.03-Claims for Different Invention Added After an Office Action 

 821.04-Rejoinder 
 821.04(a)-Rejoinder Between Product Inventions; Rejoinder Between Process Inventions 

 821.04(b)-Rejoinder of Process Requiring an Allowable Product 

 
 

 
 

 822-Claims to Inventions That Are Not Patentably Distinct in Plural Applications of Same Applicant or Assignee 

 823-Unity of Invention Under the Patent Cooperation Treaty 

 

 

 
 

 
 
 

 
 

 

 
 
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 Last Modified: 
 
 03/09/2026 20:50:54