Marking Classified Information

Physically marking classified information with appropriate classification markings serves to warn and inform holders of the degree of protection required to protect it. Other notations aid in derivative classification actions and facilitate downgrading or declassification. It is important that all classified information and material be marked to clearly convey the level of classification assigned, the portions that contain or reveal classified information, the period of time protection is required, and any other notations required for protection of the information or material.

Policy guidelines for the classification, marking, and declassification of national security information are found in the President's Executive Order 12958, Classified National Security Information, April 17, 1995. The full text of this order is available at the Security Policy Board's Internet site, Classification and marking guidelines for defense industry are in Chapter 4 of the National Industrial Security Program Operating Manual.  The full text of the NISPOM is available at the Defense Security Service Internet site,

The Information Security Oversight Office publishes a free booklet entitled Marking with instructions and illustrations for marking classified documents.

The following is a summary of the most commonly used classification and marking instructions.

Overall Classification Markings

The overall (i.e., highest) classification of a document is marked at the top and bottom of the outside cover (if there is one), the title page (if there is one), the first page, and the outside of the back cover (if there is one) or back side of the last page.

Each interior page containing classified information is marked top and bottom with the overall (i.e., highest) classification of the page. Each unclassified interior page is marked 'Unclassified" at the top and bottom. Interior pages that are For Official Use Only need to be marked only at the bottom. Blank pages require no markings.

Attachments and annexes may become separated from the basic document.  They should be marked as if they were separate documents.

Additionally, every classified document must show, on the face of the document, the agency and office that created it and date of creation. This information must be clear enough to allow someone receiving the document to contact the preparing office if questions or problems about classification arise.

U.S. documents that contain foreign government information shall be marked on the front, "THIS DOCUMENT CONTAINS FOREIGN GOVERNMENT (indicate level) INFORMATION."

Portion Marking

The title or subject of a classified document is marked with the appropriate classification abbreviation in parentheses -- (TS), (S), (C), (FOUO), or (U) immediately following and to the right of the title or subject.

Each section, part, paragraph, or similar portion of a classified document is to be marked with the appropriate classification abbreviation in parentheses immediately before the beginning of the portion. If the portion is numbered or lettered, place the abbreviation in parentheses between the letter or number and the start of the text.

Portions of U.S. documents containing foreign government information are marked to reflect the foreign country of origin as well as the appropriate classification, for example, (U.K.-C). Portions of U.S. documents containing extracts from NATO documents are marked to reflect "NATO" or "COSMIC" as well as the appropriate classification, for example, (NATO-S) or (COSMIC-TS). Further information is available at Foreign Government Classified Information.

Markings for the "Classified by," "Derived from," and "Declassify on" Lines

All classified information will be marked to reflect the source of the classification, reason for the classification, and instructions for declassification or downgrading. The markings used to show this information must appear toward the bottom on the cover, first page, title page, or in another prominent position. Nondocumentary material should show the required information on the material itself or, if not practical, in related or accompanying documentation.

"Classified by" Line: The "Classified by" line is used only on originally classified documents. It identifies the original classification authority by name or personal identifier and position and cites justification for the classification. This is followed by a "Reasons" line that cites by name or number one of the seven approved classification categories specified in Executive Order 12958.

Example of

"Derived from" Line: Any appropriately cleared employee has the authority to derivatively classify a document. The "Derived from" line cites the source document or classification guide which allowed you to determine that the information in your document is classified. The date of the source document or classification guide is to be included. If more than one source document, classification guide, or combination of these provided the derivative classification guidance, write "Multiple Sources" on the "Derived from" line. A record of these multiple sources must be maintained on or with the file copy of the document.


Example of

  • "Declassify on" Line: The classified by or derived from lines should be followed by a line that identifies when the classified information is to be declassified. This information is obtained from the "Declassify on _____" line of the source document or from a classification guide. If your document classification is derived from "Multiple Sources" and different declassification instructions apply, you must use the most restrictive declassification instruction that applies.


There are three general options for declassification instructions for documents that were originally classified under Executive Order 12958.

  • Specific Date or Event: When possible, apply a date or event for declassification that corresponds to the lapse of the information's national security sensitivity. The date or event must not exceed 10 years from the date of the original classification.
  • Ten-Year Duration: When a specific date or event cannot be determined, apply a date 10 years from the date of the original classification.
  • Exemptions: If the original classifier determines that the information is exempt from declassification at 10 years, use the letter "X" followed by the name or number of the exemption category(ies) as specified in section 1.6(d) of Executive Order 12958.

Many older documents classified prior to Executive Order 12958 still carry the declassification designation OADR -- Originating Agency's Determination Required. When one of these documents is the source document for derivative classification, the Declassify on line should read: Source document marked "OADR" Date of source (insert date).

No U.S. document shall be downgraded below the highest level of foreign government information contained in the document, nor shall it be declassified without the written approval of the foreign government that originated the information.

Classified Information Appearing in Public Media: The fact that classified information has been made public does not mean it is automatically declassified. Information remains classified unless and until it is formally declassified. If you become aware of classified or other sensitive information appearing in the public media, bring it to the attention of your security office.

Downgrading or Declassifying Classified Information: Information is downgraded or declassified based on the loss of sensitivity of the information due to the passage of time or on occurrence of a specific event. Declassification is not automatically an approval for public disclosure.

Marking Downgraded or Declassified Material: Classified information that is downgraded or declassified should be promptly and conspicuously marked to indicate the change.

Related Topics: Classification Guidelines and Distribution Controls, Foreign Government Classified Information.