MPEP § 903 — MPEP § 903
Current through: 2022-07-01

903-Classification in USPC 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Chapter 0900 

 Section 903 
 

 
 
 
 
 
 903 Classification in USPC [R-07.2022]

 Utility patents, applications, and patent application
 publications receive a classification designation under the Cooperative Patent
 Classification (CPC) system. Only design and plant applications/patents and plant
 application publications receive classification designations under USPC. See
 MPEP §
 905 for information on CPC.
 

 
 903.01 Statutory Authority [R-08.2012]

 The statutory authority for establishing and maintaining a
 classification system is given in the following statute, which states:
 

 
 35 U.S.C. 8 
 Classification of patents. 

 The Director may revise and maintain the classification by subject
 matter of United States letters patent, and such other patents and printed
 publications as may be necessary or practicable, for the purpose of determining with
 readiness and accuracy the novelty of inventions for which applications for patent
 are filed.
 

 

 

 
 903.02 Basis and Principles of Classification in USPC [R-07.2022]

 Many of the principles that form the basis of classification within
 USPC used in the U.S. Patent and Trademark Office are set forth in the “Examiner
 Handbook to the U.S. Patent Classification System” which can be accessed from either the
 intranet on the Classification Home Page ( http://ptoweb.uspto.gov/patents/classification- resources/ ) or the
 internet on the Office of Patent Classification home page ( www.uspto.gov/Classification ). Any questions not covered in this
 handbook can be directed to the Office of Patent Classification.
 

 
 903.02(a) [Reserved]

 

 

 

 
 903.02(b) Scope of a Class in the USPC [R-07.2015]

 In using any classification system, it is necessary to analyze the
 organization of the class or classes to be included in the search.
 

 The initial analysis should determine which one or ones of the
 several types of subject matter (manufacture, art, apparatus, or stock material) are
 contained in the class being considered.
 

 Further, relative to each type of subject matter, it is necessary to
 consider each of the various combinations and subcombinations set out below:
 

 Basic Subject Matter Combined with Feature for Some Additional
 Purpose. The added purpose is in excess of the scope of the subject
 matter for the class, as defined in the class definition; e.g., adding a sifter to a
 stone crusher which gives the added function of separating the crushed stone.
 

 Basic Subject Matter Combined with Perfecting Feature. Features
 may be added to the basic subject matter which do not change the character thereof,
 but do perfect it for its intended purpose; e.g., an overload release means tends to
 perfect a stonecrusher by providing means to stop it on overload and thus prevent
 ruining the machine. However, this perfecting combined feature adds nothing to the
 basic character of the machine.
 

 Basic Subject Matter. The combination of features necessary and
 essential to the fundamental character of the subject matter treated; e.g., a
 stonecrusher requires a minimum number of features as essential before it can
 function as such.
 

 Subcombinations Specialized to Basic Subject Matter. Each type of
 basic subject matter may have subcombinations specialized to use therewith; e.g., the
 crushing element of a stonecrusher.
 

 Subcombinations of General Utility. Each type of basic subject
 matter may have subcombinations which have utility with other and different types of
 subject matter; e.g., the machine elements of a stonecrusher. Subcombinations of this
 character usually are provided for in some general class so that the examiner should
 determine in each instance where they are classified.
 

 

 

 
 903.03 Availability of Foreign Patents [R-01.2024]

 Many foreign patent documents received in the Office before October 1,
 1995 were placed in the shoes in the Technology Center (TCs), according to either the
 United States Patent Classification System (USPC) or, in relatively few instances, the
 International Patent Classification (IPC) system. Foreign patents received by the Office
 after October 1, 1995 are available on the USPTO’s automated search system, internet
 sites, and the Scientific and Technical Information Center (STIC) collections.
 

 If the examiner desires to update the USPC classification of a foreign
 patent by changing, canceling, or adding copies, they should forward the patent (or
 bibliographic information) to their supervisory patent classifier with a request for the
 desired transaction attached.
 

 The Foreign Patents Service Center manages the Main Library of STIC.
 STIC’s collections are international in scope and include foreign patents, non-patent
 literature, designs, trademarks, and legal information. There is an assortment of
 resources which reflect the information needs of examiners and researchers working in
 various fields of science and technology. The staff is experienced in foreign patent
 data retrieval, patent family searches, and document retrieval services for non-patent
 literature in the STIC collections. 
 

 Examiners confronted with language problems in classifying
 foreign-language patents may call upon the Translations Service Center of STIC for
 assistance (see MPEP §
 901.06(a) ). In addition, the Translations Service Center
 retains copies of translated foreign patents in the database.
 

 

 
 903.04 Classifying Applications for Publication as a Plant Patent
 Application Publication in USPC [R-07.2022]
 

 Most patent applications filed on or after November 29, 2000, are
 published as a patent application publication pursuant to 35 U.S.C. 122(b) ,
 unless certain exceptions apply. See MPEP § 1120 .
 

 U.S. utility patents and U.S. utility patent application
 publications published after December 31, 2014 do not receive classifications within the
 USPC and only receive classification designations within the CPC. Only U.S. design and
 plant patents and U.S. plant patent application publications continue to receive
 classifications within the USPC. See MPEP § 905 for information on CPC.
 

 Plant patent application publications are given a primary
 classification (equivalent to an original classification), and may also be given a
 secondary classification (equivalent to a cross reference). While there may be only one
 primary classification for a single plant patent application publication, there may be
 any number of secondary classifications. The selection of a primary classification of a
 plant patent application publication is based on the application’s main inventive
 concept using the claim as a guide. A primary classification could be any U.S.
 class/subclass (except cross reference art collections, digests and foreign art
 collection subclasses). A secondary classification is based on other inventive concepts
 (mandatory) or valuable disclosure (discretionary), and may be any U.S. class/subclass
 (including cross reference collections and digests, but excluding foreign art collection
 subclasses). The classification of a plant patent application publication is printed on
 the front page of the publication.
 

 At least 9 weeks prior to the projected publication date, applications
 are classified using programs designed to enable entry of certain data required for
 publication of patent applications. Applications are classified by giving each
 application at least a primary classification and an international classification. The
 suggested international classification(s) corresponding to each assigned U.S.
 classification is provided. In addition, if a figure is to be published, the figure is
 selected at the time of classification.
 

 

 
 903.05 Addition, Deletion, or Transfer of U.S. Design Patents by USPC
 Classification [R-07.2022]
 

 Requests for addition, deletion, or transfer of official copies of U.S.
 patents may be carried out by using the Patent Post Publication Classification Manager,
 which are available online from the Classification Home Page under the "Additional
 Resources" heading. The Classification Home Page is accessible from the desktop via the
 Patent Examiner’s Toolkit. The Classification Manager tool is available only for design
 patents.
 

 Using these tools, examiners can request the following
 transactions:
 

 
 (A) Add any classification(s) from the U.S. Patent Classification
 system as a cross-reference (XR) classification to a patent or a secondary
 classification to a patent application publication.
 

 (B) Delete XR classification(s) or secondary classification assigned
 to the Technology Center (TC) of the person requesting the deletion.
 

 (C) Change original classifications (ORs) or primary patent
 application publication classification to a classification in the TC of the person
 requesting the change.
 

 (D) Add or delete any International Patent Classification system
 (IPC) classification to a patent.
 

 
 

 
 903.06 Harmonized Subclasses [R-07.2015]

 The U.S. Patent Classification System (USPC) includes subclasses that
 have been harmonized with subclasses from the European Patent Office (EPO) and the Japan
 Patent Office (JPO). Subclasses that have been harmonized have a designation of “EPO,”
 “JPO,” or “EPO/JPO” in parentheses following the subclass title to indicate if the
 subclass has been harmonized with the EPO or JPO or with both systems.
 

 

 
 903.07 Classifying and Cross-Referencing Design and Plant Applications
 at Allowance [R-01.2024]
 

 U.S. utility patents and U.S. utility patent application
 publications published after December 31, 2014 do not receive classifications within the
 USPC and only receive classification designations within the CPC. Only U.S. design and
 plant patents and U.S. plant patent application publications continue to receive
 classifications within the USPC. 
 

 When an application is passed to issue, it is the duty of each primary
 examiner to personally review the original classification and cross-referencing made by
 their assistants in the issuing classification boxes on the Issue Classification sheet.
 This form provides space for the full name of the “Primary Examiner” to show that the
 review has been made. An examiner with full signatory authority who acts personally on
 an application and sends it to issue should stamp and sign their name on the Issue
 Classification sheet ONLY in the “Primary Examiner” space.
 

 An application, properly classified at the start of examination, may be
 classified differently when it is ready for allowance. The allowed claim should be
 reviewed in order to determine the subject matter covered thereby. It is the disclosed
 subject matter covered by the allowed claim that determines the original and any
 mandatory cross-reference classification of U.S. patents.
 

 After all mandatory classifications have been determined, the
 classification to be designated as the original (OR) is determined. If all mandatory
 classifications are in the same class, the original classification is the mandatory
 classification that, looking at the schedule from the top down, is the most indented
 subclass array in which any classifications are assigned, in certain circumstances
 (e.g., the genus-species array), however, modifications of this rule may apply. See the
 “Examiner Handbook on the Use of the U.S. Patent Classification System”.
 

 If the mandatory classifications are in different classes, the original
 classification is determined by considering, in turn, the following criteria:
 

 
 (A) selection based on priority of statutory category of
 invention,
 

 (B) selection based on superiority of types of subject matter,
 and
 

 (C) selection among classes in the “related subject” listing at the
 front of the manual of classification.
 

 
 It should be noted that the criteria, supra, may be
 superseded by
 

 
 (A) special circumstances,

 (B) prior placement of patents for a particular body of art, or 

 (C) particular class lines and class notes.

 
 Once the controlling class is determined, the original classification,
 looking at the schedule from the top down, is the mandatory classification that is the
 most indented subclass of the first subclass array in which any classifications are
 assigned.
 

 For a more complete discussion of this subject, see the “Examiner
 Handbook on the Use of the U.S. Patent Classification System” which is available online
 to USPTO personnel from the Classification Home Page under the heading "General
 Training". The Classification Home Page ( https://ptoweb.uspto.gov/patents/classification-resources/ ) is
 accessible from the desktop via the Patent Examiner’s Toolkit.
 

 Once the original classification is determined, all remaining mandatory
 classifications are designated as cross-references, as are any additional discretionary
 classifications that the examiner wishes to apply to the patent.
 

 The examiner must complete the issue classification sheet to indicate
 the class and subclass in which the patent should be classified as an original and also
 the classifications in which it should appear as a cross-reference. The examiner should
 be certain that all subclasses into which cross-references are placed are still valid. 
 

 All examiners must include alpha subclass designators in the issuing
 classification boxes on the issue classification sheet at the time of issue when
 appropriate. This applies to both the original classification and the cross-reference
 classification. Any time that a patent is being issued in or cross-referenced to a
 subclass containing alpha subclasses, the alpha designation for the proper alpha
 subclass must be included. No other designation is permissible. Inclusion of only the
 numeric designation of a subclass which includes an alpha subclass designation is an
 incomplete and improper entry. A numeric subclass from which alpha subclasses have been
 created is designated with an “R” (denoting residual), and if the patent does not fit an
 indented alpha subclass, the “R” designation must be included. It is permissible to
 place multiple copies of a patent into a single set of alpha subclasses.
 

 Digests and cross-reference art collections should also be included in
 the issuing classification boxes on the issue classification sheet, but the original
 classification must never be a digest or cross-reference art collection. The indication
 for a copy of a patent in a digest or cross-reference art collection must be in the
 cross-reference area of the issuing classification boxes. A digest must be identified by
 class number, alpha characters DIG, and appropriate digest number.
 

 U.S. patents cannot be classified in subclasses beginning with “FOR,”
 since these are exclusively for foreign patents. 
 

APPLICATIONS IN ISSUE
 Where an official classification order affects an application
 already passed to issue, the Office of Patent Classification oversees any necessary
 changes. Patents issuing from applications which already have been sent to the
 printer will be reclassified.
 

 
 903.07(a) Cross-Referencing Design and Plant Applications — Keep
 Systematic Notes During Prosecution [R-07.2022]
 

 Throughout the examination of a design or plant application,
 systematic notes should be kept as to cross-references needed either due to claimed
 or unclaimed disclosure. Examiners handling related subject matter should be
 consulted during prosecution (whether they handle larger unclaimed combinations or
 claimed or unclaimed, but disclosed, subcombinations), and asked if cross-references
 are needed.
 

 Each consultation involving a question of the propriety of the
 classification of subject matter and/or the need for a cross-reference must be
 recorded in the SEARCH NOTES box on the file wrapper and must include: the name of
 each examiner consulted, the date that the consultation took place, and the results
 of the consultation including the consulted examiners’ or examiner’s indication of
 where claimed subject matter is properly classified and where subject matter
 disclosed but unclaimed is properly classified and whether or not a cross-reference
 is needed. 
 

 A cross-reference MUST be provided for all CLAIMED disclosure where
 possible and inserted in the issuing classification boxes at time of issue.
 

 

 

 
 903.08 [Reserved]

 
 903.08(a) [Reserved]

 

 
 903.08(b) [Reserved]

 

 
 903.08(c) [Reserved]

 

 
 903.08(d) [Reserved]

 

 
 903.08(e) [Reserved]

 

 

 
 903.09 [Reserved]

 
 903.09(a) [Reserved]

 

 

 

 [top] 

 

 

 
 

 
 

 

 

 

 
 
 
 901-Prior Art 
 901.01-Canceled Matter in U.S. Patent Files 
 901.01(a)-Ordering of Patented and Abandoned Provisional and Nonprovisional Application Files 

 
 

 901.02-Abandoned Applications 

 901.03-Pending Applications 

 901.04-U.S. Patents 
 901.04(a)-Kind Codes 

 
 

 901.05-Foreign Patent Documents 
 901.05(a)-Citation Data 

 901.05(b)-Other Significant Data 

 901.05(c)-Obtaining Copies 

 901.05(d)-Translation 

 
 

 901.06-Nonpatent Publications 
 901.06(a)-Scientific and Technical Information Center (STIC) 

 901.06(b)-Borrowed Publications 

 901.06(c)-Alien Property Custodian Publications 

 901.06(d)-Abstracts, Abbreviatures, and Defensive Publications 

 
 

 901.07-Patent Family Information 

 901.08-Global Dossier Public Access 

 
 

 902-Search Tools and Classification Information 
 902.01-Classification Manual for the U.S. Patent Classification System 
 902.01(a)-Index to the U.S. Patent Classification System 

 
 

 902.02-Class and Subclass Definitions in USPC 
 902.02(a)-Definition Notes in USPC 

 902.02(b)-[Reserved] 

 
 

 902.03-Classification Information 
 902.03(a)-Patent Classification Home Page on the Internet 

 902.03(b)-Patent Classification Home Page on the USPTO Intranet 

 902.03(c)-[Reserved] 

 902.03(d)-[Reserved] 

 902.03(e)-Automated Search Tools: PE2E SEARCH 

 
 

 
 

 903-Classification in USPC 
 903.01-Statutory Authority 

 903.02-Basis and Principles of Classification in USPC 
 903.02(a)-[Reserved] 

 903.02(b)-Scope of a Class in the USPC 

 
 

 903.03-Availability of Foreign Patents 

 903.04-Classifying Applications for Publication as a Plant Patent Application Publication in USPC 

 903.05-Addition, Deletion, or Transfer of U.S. Design Patents by USPC Classification 

 903.06-Harmonized Subclasses 

 903.07-Classifying and Cross-Referencing Design and Plant Applications at Allowance 
 903.07(a)-Cross-Referencing Design and Plant Applications — Keep Systematic Notes During Prosecution 

 
 

 903.08-[Reserved] 
 903.08(a)-[Reserved] 

 903.08(b)-[Reserved] 

 903.08(c)-[Reserved] 

 903.08(d)-[Reserved] 

 903.08(e)-[Reserved] 

 
 

 903.09-[Reserved] 
 903.09(a)-[Reserved] 

 
 

 
 

 904-How to Search 
 904.01-Analysis of Claims 
 904.01(a)-Variant Embodiments Within Scope of Claim 

 904.01(b)-Equivalents 

 904.01(c)-Analogous Arts 

 
 

 904.02-General Search Guidelines 
 904.02(a)-Classified Search 

 904.02(b)-Search Tool Selection 

 904.02(c)-Internet Searching 

 
 

 904.03-Conducting the Search 

 904.04-Search of Related Post-Grant Proceedings 

 
 

 905-Cooperative Patent Classification 
 905.01-Classification Scheme for CPC 
 905.01(a)-CPC Titles 
 905.01(a)(1)-References within CPC Titles 

 905.01(a)(2)-Notes Found in CPC schemes 

 905.01(a)(3)-Warnings Found in CPC schemes 

 905.01(a)(4)-Guidance Headings Found in CPC Schemes 

 
 

 
 

 905.02-CPC Definitions 

 905.03-Classifying in CPC 
 905.03(a)-The CPC Database 

 905.03(b)-Approach to classification in CPC 

 905.03(c)-Combination Sets 

 
 

 
 

 906-International Classification of Patents for Inventions 

 907-Locarno Classification Designations 

 908-[Reserved] 

 909-Routing and Docketing of Applications 
 909.01-Assignment, Transfer and Classification Challenges under Cooperative Patent Classification (CPC) 
 909.01(a)-New Applications in CPC 

 909.01(b)-Classification and Assignment to Examiner in CPC 

 909.01(c)-Immediate Inspection of Amendments 

 909.01(d)-Classification Challenge Procedure in CPC 

 
 

 909.02-Applications: Assignment and Transfer in USPC 
 909.02(a)-New Design and Plant Patent Applications under 35 U.S.C. 161 

 909.02(b)-Classification and Assignment to Examiner 

 909.02(c)-Reserved 

 909.02(d)-Transfer Procedure 

 909.02(e)-General Guidelines Governing the Assignment of Nonprovisional Design and Plant Applications for Examination 

 
 

 
 

 

 

 
 

 
 
 

 
 

 

 
 
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 Last Modified: 
 
 03/09/2026 20:49:44