Archiving Requirements

Proper archiving of invoices is a legal obligation in Poland with serious consequences for non-compliance. The rules are set out in the VAT Act, the Tax Ordinance (Ordynacja podatkowa), and the Accounting Act (Ustawa o rachunkowosci). This article covers retention periods, storage formats, integrity requirements, and the impact of KSeF on archiving.

Retention Period

Invoices and related tax documentation must be retained for 5 years from the end of the calendar year in which the tax payment was due (Art. 112 of the VAT Act and Art. 86 section 1 of the Tax Ordinance).

For example, an invoice issued in March 2026 relates to a VAT settlement due in April 2026 (or March 2026 for monthly filers). The retention period runs from December 31, 2026, and the documents must be kept until December 31, 2031.

This 5-year rule applies to:

• All issued (sales) invoices
• All received (purchase) invoices
• Corrective invoices and correction notes
• Advance invoices and final invoices
• JPK_VAT records and summary files
• Supporting documentation (delivery confirmations, contracts, payment records related to invoices)

If a tax proceeding or audit is in progress at the end of the 5-year period, the retention obligation extends until the proceedings are concluded.

Storage Format

Since 2022, Polish law treats digital and paper storage as fully equivalent. There is no requirement to store paper originals if a compliant digital copy exists, and vice versa. A business may choose to:

• Store all invoices digitally (scanned paper invoices or natively digital invoices)
• Store all invoices on paper (printed electronic invoices)
• Use a combination of both

The key requirement is that whichever format is used, the stored invoices must meet the three quality criteria defined in Art. 106m of the VAT Act.

Quality Requirements: Authenticity, Integrity, Legibility

Art. 106m requires that from the moment of issue until the end of the retention period, every invoice must maintain:

• Authenticity of origin (autentycznosc pochodzenia) — it must be possible to verify the identity of the party that issued the invoice. The seller's identity must be provable and traceable
• Integrity of content (integralnosc tresci) — the data on the invoice must not have been altered after issuance. No fields may be modified, deleted, or added
• Legibility (czytelnosc) — the invoice must be readable by a human without special tools or decoding. Faded thermal paper receipts or corrupted PDF files do not meet this requirement

The taxpayer has freedom in choosing how to ensure these three properties. The VAT Act recognizes several methods:

Business Controls (Kontrole biznesowe)

The most common approach for paper-based workflows. The taxpayer establishes internal procedures that create a reliable audit trail linking the invoice to the underlying transaction (delivery note, purchase order, payment confirmation). If these controls reliably ensure authenticity and integrity, no additional technical measures are required.

EDI (Electronic Data Interchange)

Invoices exchanged via EDI systems that comply with the European Commission Recommendation 1994/820/EC are automatically considered to meet the authenticity and integrity requirements, provided the agreement between trading partners specifies the use of procedures guaranteeing those properties.

Qualified Electronic Signature or Seal

An invoice signed with a qualified electronic signature (kwalifikowany podpis elektroniczny) under the eIDAS regulation, or sealed with a qualified electronic seal, inherently guarantees both authenticity and integrity.

KSeF Structured Invoices

Invoices issued and received through the National e-Invoicing System (Krajowy System e-Faktur, KSeF) are automatically deemed to meet all three requirements, as the system itself guarantees identity verification, data integrity, and standardized readability.

KSeF as an Archive

The KSeF system stores all structured invoices for 10 years from the date of issue. This is significantly longer than the standard 5-year retention obligation. During this period, invoices are available for download by both the issuer and the recipient through the KSeF platform.

Does KSeF Replace the Archiving Obligation?

For structured invoices issued through KSeF, the system effectively serves as a compliant archive. The taxpayer does not need to separately store these invoices, as KSeF meets all requirements of Art. 106m and exceeds the minimum retention period.

However, KSeF does not eliminate all archiving responsibilities:

• Pre-KSeF invoices — invoices issued before the taxpayer's KSeF onboarding must still be archived through traditional means for the full retention period
• Accompanying documents — contracts, delivery notes, payment confirmations, and other documents that support the invoices are not stored in KSeF and must be archived separately
• Non-structured invoices — proforma invoices, internal documents, and invoices from foreign suppliers not using KSeF are outside the system's scope
• JPK audit files — while KSeF stores invoices, the SAF-T (JPK) files and their underlying data must still be retained by the taxpayer

Storage Abroad

Polish law permits storing invoices outside of Poland, provided the following conditions are met:

• The storage location is within an EU member state or an EFTA state
• The taxpayer must provide the tax authority with immediate, full online access to the invoices on demand (Art. 112a(2))
• The stored invoices must be downloadable and printable without delay
• The taxpayer must inform the head of the tax office about the storage location

Storing invoices outside the EU is generally not permitted unless there is a specific international agreement in place.

Backup and Data Security

While the VAT Act does not prescribe specific technical backup standards, the practical consequences of losing invoices during the retention period are severe — the taxpayer may lose the right to deduct input VAT and may face estimated tax assessments. Best practices include:

• Redundant storage — maintain at least two copies of digital invoice archives in physically separate locations
• Regular integrity checks — periodically verify that archived files are not corrupted, especially for long-term storage on optical media or older hard drives
• Access control — restrict who can modify or delete archived invoices; audit logs are recommended
• Format longevity — use widely supported, non-proprietary formats (PDF/A for scanned documents, XML for structured data) to ensure files remain readable years later
• Disaster recovery plan — document procedures for restoring invoice archives in case of data loss, hardware failure, or ransomware attacks
• Cloud storage — acceptable if the data center is in the EU and the provider can guarantee data integrity and availability for the full retention period