To preserve the Defence Line of Amsterdam in its entirety, it was inscribed on the UNESCO World Heritage List in December 1996. It is therefore recognised as an international monument of outstanding universal significance. Extensive research and numerous recommendations and consultations preceded the acquisition of this status. On the basis of the six general cultural guidelines of the 1972 World Heritage Convention, the Defence Line was recognised on the basis of the following three criteria:
In the first place a cultural World Heritage must exhibit an important interchange in the development of technology, architecture, town-planning or landscape design. Secondly, it must be an outstanding example of a type of building or landscape which illustrates one or more significant stages in human history. Finally, it must be an outstanding example of a traditional settlement, land-use or sea-use which is representative of a culture, especially when it has become vulnerable under the impact of irreversible change.

When the Defence Line of Amsterdam was inscribed, the following considerations applied:

The Committee established that the Defence Line of Amsterdam is of outstanding universal significance as an exceptional example of an extensive, connected defence system of the modern age, which has remained intact and well-preserved since its construction at the end of the 19th century. The Defence Line of Amsterdam is also notable for the unique way in which Dutch ingenuity for hydraulic engineering has been incorporated into the defence of the country's capital, making maximum use of the possibilities offered by the landscape.

Inscription of the Defence Line of Amsterdam on the World Heritage List means there is an obligation to preserve and possibly enhance its qualities. However, because of drastic environmental developments, the former inundation zone in the Haarlemmermeerpolder has not been inscribed as a World Heritage site. The zone has been reduced here, leaving the ‘Geniedijk’ (defence line dyke or embankment) as the basis for the inscribed area. Parts of the Defence Line of Amsterdam that lie within the ring, such as depots and barracks, have also not been placed on the World Heritage List by name. Interesting is that some of the Defence Line of Amsterdam coincides with the World Heritage site, the Beemster Polder, which was inscribed in 1999.