The NCS is the Codification system used by the armed forces of all NATO countries in order to facilitate military Logistics operations across NATO. The NCS is an "invisible partner" in the day-to-day business of Logistics, and has been also adopted by 22 non-NATO countries under a specific programme which allows exchange of Codification data by applying NCS disciplines.

The NCS is based on the philosophy of the "Item of Supply" (IOS) concept. This portrays an object or group of objects which has been defined by a qualified Logistics service to meet a specific requirement. The initial step for item identification is the allocation of an Item Name, followed by the selection of the appropriate NATO Supply Group and Class. Afterwards Identification Guides are used to adequately describe the item and its characteristics, thus differentiating it from other IOS, and establishing the supplementary data necessary for Logistics management.

The next step of the process is comprised of the addition of manufacturers references and management information, when these are available. However, it should be noted that the reference number without the item name does not unambiguously identify the item. Finally the NATO Stock Number (NSN), which uniquely identifies an IOS all through its lifecycle, is assigned.

The NCS encompasses as well two features that are unavailable in other item identification systems: 1) an identification approach based on the IOS concept that is applicable to all types of commodities, and 2) a gateway to a vast range of Logistics information required by military Logisticians, and not available in commercial identification schemes.