Last updated 14 October 2026. By Demetre E. Katsouris, Managing Partner, Katsouris Law Firm.
The short answer: Greece keeps information about your property in several places that have never talked to each other: the tax authority’s property declaration (E9, which gives each property an ATAK number), the Cadastre (which gives it a KAEK number), the register of leases, the short-term rental register, the electricity supplier and the planning office. Law 5222/2025 (Article 217) creates MIDA, a single digital register that links them, with the ATAK and KAEK as the matching key. The consequence is simple: a property that is 95 sq.m. in the E9, 102 sq.m. at the Cadastre and 110 sq.m. in the deed will be flagged, and the owner will be asked to explain. Owners who live abroad, whose records were filed by different people over decades, are the ones most likely to be flagged. The time to reconcile is before the system asks.
What MIDA records
For every property: type, surface area, location, floor, electricity supply, construction status and declared use. Declared use means whether it is your main or secondary residence, whether it is let on a long lease or short-term, whether it is used free of charge by a relative, or is vacant. The register is populated from the existing sources and will later connect to the Cadastre’s unified property registry once that is operational. Full activation, originally expected in late 2025, is now planned during 2026.
The five records
1. The E9 declaration and the ATAK. This is what the tax authority thinks you own: surface, floor, year of construction, share, type of right (full ownership, bare ownership, usufruct). Every ENFIA bill is calculated from it. Common errors for owners abroad: the property is still declared in a deceased parent’s name; the share is wrong after an inheritance; a storage room or parking space was never added; the year of construction is missing, which raises the ENFIA. Corrections are made by amending declaration.
2. The Cadastre entry and the KAEK. This is the legal record of ownership and boundaries. Common errors: the owner recorded is the person who bought in 1978, not the heir; the registered area does not match the deed; a co-owner’s share is missing; the property shows as “unknown owner”. Corrections range from a simple application for an obvious error to a court procedure. We cover them in a separate article.
3. Lease declarations. Every long-term lease should have been declared electronically when it began and when it ended. If a tenant left in 2022 and no termination was filed, the tax authority still shows the property as let and you as receiving rent. Under MIDA that will contradict a declaration that the property is vacant or used by family.
4. Short-term rental registration. If the property is on a platform, it must carry a registration number issued to you, and the nights and income reported by the platform since May 2026 will be cross-checked against your return. If a previous owner’s number is still being used, or a manager registered the property in their own name, the records will not match.
5. The building record. The electronic building identity, the building permit and any legalisation of unpermitted works describe what is actually built. From tax year 2027 the surface in the building identity will be used for ENFIA where it is smaller than the E9 figure. Where it is larger, the question becomes why the difference was never declared.
Why it matters
Three consequences follow from a mismatch. ENFIA may be reassessed, with interest, for past years. A sale or gift stalls while the notary’s certificates are reconciled, because the tax clearance, the ENFIA certificate and the Cadastre extract must describe the same property. And a declared use that does not match the lease records invites a tax audit of rental income.
There is also an upside. A property whose records all agree is faster and cheaper to sell, let, gift or mortgage, and an heir abroad inherits a file rather than a puzzle.
What we do for owners abroad
We pull the four public records — E9 printout, Cadastre extract, lease history, building identity or permit file — place them side by side with the deed, and produce a one-page reconciliation showing each discrepancy and how it is fixed: amending E9, Cadastre application, termination declaration, engineer’s certificate. Most files have two or three small discrepancies that take a month to clear. A few have one large one, usually at the Cadastre, that takes longer, and it is better to know now.
Frequently asked questions
I have not filed an E9 since my father died in 2015. Where do I start? With the inheritance. The E9 follows the acceptance deed; it cannot be corrected into your name before you are the owner of record.
My apartment is let to my cousin for free. Does that need declaring? Yes. Free use by a relative is a declared use category, and the tax authority may impute income if it is not declared.
Will MIDA replace the Cadastre? No. The Cadastre remains the legal title record. MIDA reads from it.
Can my accountant do all this? The E9 and lease declarations, yes. The Cadastre and the building record need a lawyer and an engineer. The reconciliation needs all three to look at the same page.
This article is general information, not legal advice; it reflects the position on the date above and may change.
To have your property’s records reconciled before MIDA goes live, send us the address and a copy of the deed: info@katslaw.eu or +30 210 8982 864.
