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  2. National Stock Numbers (NSN)

National Stock Numbers (NSN)

ALCL 105
Alternate Definition

The 13-digit number that identifies a stock item consisting of the 4-digit Federal Supply Classification (FSC) code plus the 9-digit National Item Identification Number (NIIN) and arranged as follows: 9999-00-999-9999. 

General Information

NSN Origin

The NSN replaced the Federal Stock Number (FSN) in 1974. The FSN was an 11-Digit Numeric Code developed by the DoD in 1949 to identify items in the Army-Navy Catalog System. Two digits were added to the 11-Digit FSN in positions 5 and 6 to signify the country of origin of the numeric code. In the instance of the US, this code was 00. The coding system has been adopted by the member nations of the North Atlantic Treaty Organization (NATO), and other non-member nations as well, so the system has come to be known as the NATO Stock Number System, although the term NSN has stuck in the US. Now, both NSN and NATO Stock Number are interchangeable terms for the same codification system.


An NSN is the official label applied to an item of supply that is repeatedly procured, stocked, stored, issued, and used throughout the NATO supply system. It is a unique, item identifying, series of numbers. When a NSN is assigned to an item of supply, data is assembled to describe the item, including the item name, manufacturer's reference number, unit price, and physical and performance characteristics.

NSNs are an essential part of the military logistics supply chain used in managing, moving, storing, and disposing of material. NSNs are used to identify and manage almost every imaginable item from aircraft parts to toilet paper, from space vehicles to nuts and bolts. There are over 17 million active NSNs and more than 10 million historical NSNs (no longer used). These NSNs represent more than 42 million manufacturer's part numbers from more than 2.6 million suppliers.

Standard Language for Supply

Using a standard language for supply is increasingly important as it promotes coordination between the military services, which results in increased readiness and availability to all users. The NSN is also critical to the effective integration of the services in joint military endeavors.

The NSN enables military services to access the same information and identify like items of supply. Mechanics, technical inspectors, maintenance, and other supply personnel can review NSN data to locate information on all parts needed to maintain and support operations. The use of NSNs provides logistics managers, procurement personnel, operations planners, and industrial base assessment personnel with a standard method of identifying and tracking items of supply in-storage, in-process, in-transit and in-theater. The use of NSNs facilitates the standardization of item names, supply language, characteristics and management data and aids in reducing duplicate items in Government inventories.

NSN Assignment

Manufacturers and suppliers do not have the authority to request a NSN. This is usually accomplished once a requirement/need for that manufacturer's/supplier's item has been identified by a military service and certain federal and civil agencies. Requests are forwarded through the appropriate supply chain for cataloging and then forwarded to Defense Logistics Agency Logistics Information Service (DLIS). Located in Battle Creek, Michigan, DLIS assigns all NSNs.

Whenever a new weapon system is developed, the DoD Component responsible for the new weapon system will identify the spares needed to maintain the weapon system throughout the life cycle. Spares that do not have NSNs assigned are identified and requests for NSN assignment are sent to DLIS by the DoD Component, and DLIS then processes the requests and assigns new NSNs.

Other materials, not tied specifically to a weapon system, can generate the need for NSN assignment as well. Each DoD Component has a unique process for identifying a requirement for new NSNs. It starts with a Warfighter need for an item which generates an order. The order is typically submitted using a manufacturer's reference number on a DD Form 1348-6, through the DoD Component supply system.


Each NSN assigned to an item of supply is the result of a careful review process known as cataloging. This is the process whereby each item of supply is named, assigned an FSC code, described to identify all known characteristics and performance data, and ultimately assigned a NSN. This information is contained and maintained in the Web Federal Logistics Information System (WebFLIS), which is managed by the DLIS, which is the only organization authorized to assign NSNs. Requests for NSNs are initiated whenever a non-stocked item is repeatedly ordered or when a new weapons system is being developed.


Whenever a new weapon system is deployed by a military service, the service engages in an upfront review known as a provisioning process. This process identifies all potential spares to ensure weapon system support throughout the life cycle of the weapon system and is essential to properly provide support to the warfighter.

During the provisioning process, all potential spare parts are identified and requests for NSN assignment are submitted to DLIS. During NSN assignment, a wide range of logistics data is assembled to describe the item. This information includes the item name, manufacturer's part number, unit price, physical and performance characteristics, shipping data, special handling, storage, shelf life, and information associated with how to dispose of the item when no longer needed in the inventory. Throughout the life of the NSN, this data is routinely updated to include new manufacturers, price changes, part number changes or other changes affecting the support, logistics data, or characteristics of the item.

Stock Numbering Criteria

For items of supply that are recurrently used, bought, stocked, or distributed, DLIS will ensure that the NSN assigned is the only one distinct combination of numerals used to identify the same item throughout the federal supply system. In NSN assignment, DLIS will include:

  • Items selected for central management, procurement, and stockage, including both centrally and locally procured items
  • Items stocked in the main or consolidated supply component of a consumer installation to provide supply support for area requisitioners
  • Items for which two or more material demands or requisitions are recorded within a 180-dayperiod, without regard to the participating activity from which the demands were received
    • The criteria also apply to items procured directly from a commercial source for immediate use.
  • Items provided through the Foreign Military Sales (FMS) Program, NATO agreements, and other bilateral government agreements
  • Other items that, at the option of the participating activity, are required to comply with logistics programs where identification by NSN is essential
  • The FLIS item unique identification indicator when required in accordance with DoD Instruction (DoDI) 8320.04, Item Unique Identification (IUID) Standards for Tangible Personal Property

In NSN assignment, DLIS will exclude:

  • Items procured on a one-time basis for immediate use in research and development, experimentation, construction, installation, and maintenance
  • Items provided by contractors to fulfill service contracts that may provide for overhaul and repair of specified equipment if such items are consumed in the overhaul cycle and do not enter the logistics system
  • Ships, aircraft, and other major end items for which management and control are exercised through the application of IUID systems
  • Printed forms, manuals, books, or other printed materials subject to central administrative numbering controls within a bureau, service, or command
  • Items obtained through overseas procurement and intended solely for overseas use
  • Items procured with non-appropriated funds
  • Items manufactured locally for use solely by the manufacturing activity
  • Medical items that are:
    • Without an investigational new drug approval or new drug application when such is required and enforced by the Food and Drug Administration (FDA)
    • Unique to a single patient or require special fitting, such as orthopedic appliances
    • Animal blood products, such as sheep cells
  • Subsistence items supplied to the commissary resale system

Benefits derived from NSN’s

Perhaps the most significant and far-reaching benefit of the NSN is that it provides life cycle management of items of supply, from requisition to acquisition to maintenance to disposal. Other benefits include the following

  • Reducing downtime by enabling procurement personnel to quickly identify, locate, and order parts or supplies
  • Accounting for existing inventory
  • Identifying shelf life of an item of supply
  • Maximizing the use of available spares by identifying items of supply that are interchangeable or substitutable
  • Providing pricing information, which is valuable when negotiating contracts and managing military budgets
  • Improving cycle times for design, manufacture, and repair processes while extending weapon system life cycles
  • Centralizing item information on all items managed
  • Providing built-in protection for safeguarding proprietary information and limiting access to only those entities requiring such information
  • Recording multiple manufacturers on NSNs which increases supportability
  • Aiding in identifying duplicate items of supply