KAEK vs ATAK: the two Greek property numbers explained

The Hellenic Cadastre (Ελληνικό Κτηματολόγιο) is the public register of land and property rights set up under Law 4512/2018. It is organised by parcel, and each parcel has a KAEK (Κωδικός Αριθμός Εθνικού Κτηματολογίου).

The ΑΤΑΚ (Αριθμός Ταυτότητας Ακινήτου, property identity number) belongs to AADE, the Independent Authority for Public Revenue. AADE uses it to identify each property in the owner's E9, the declaration that lists a taxpayer's real estate. When an E9 is created automatically after a sale, the description of the property is filled in from the data linked to its ΑΤΑΚ.

In short: the KAEK answers "which piece of land or which unit is this on the map?" The ΑΤΑΚ answers "which property is this in the owner's tax file?"

A KAEK has 12 digits, from the largest area to the smallest: the prefecture, the municipality or community, the cadastral sector, the cadastral unit and finally the parcel number. A divided property, such as a flat in a block, adds two numbers after slashes: the first for the building, the second for the unit.

The Cadastre's public map (maps.ktimatologio.gr) shows the parcel outline, area and KAEK without logging in. Ownership shares, mortgages and lawsuits are on the cadastral sheet, which only owners and people with a legitimate interest can get. Our guide to the KAEK explains this in more detail.

• Who issues it: AADE, through the E9 property declaration.
• Where an owner finds it: in the E9 application on myAADE, where the printout of the owner's property list shows the ΑΤΑΚ for each entry.
• When it comes up in a sale: the seller's digital transfer tax declaration refers to the property's ΑΤΑΚ. Since July 2023, once the notary uploads the deed to the myPROPERTY application, AADE creates the E9 changes for buyer and seller automatically.
• When it comes up after a sale: AADE's short-term rental registry asks for the property's ΑΤΑΚ before it issues the registry number (ΑΜΑ) that must appear on every listing.

The Cadastre and AADE keep separate records, built at different times and for different purposes. The cadastral record comes from the cadastral survey and the deeds registered since. The E9 is the owner's tax declaration. So the area, the description, or even the number of separate units can differ between the two. A storage room or parking space might be its own entry in one system and part of the flat in the other.

Press reports in December 2025 described government plans for a single property ID that would link the ΑΤΑΚ, the KAEK and other registers. Until something like that is in place, do not assume the two records have been checked against each other. Ask your lawyer and accountant to do it.

A mismatch is not necessarily a problem, but it is a red flag for professional review. Ask why the records differ before you sign, not after.

• Lawyer: the full KAEK, the cadastral sheet and extract, and whether they match the seller's title deed and the property you are actually buying.
• Civil engineer: whether the parcel outline and area in the Cadastre match the topographic plan and what stands on the ground.
• Accountant: the seller's E9 entries and ΑΤΑΚ, and what your own E9 should show after the sale.
• If you plan short-term letting: the accountant registers the property in AADE's registry with its ΑΤΑΚ. Whether the property may be let that way is a separate question for your lawyer.