Observatory › Tax and returns › The new Testo unico delle imposte sui redditi (consolidated income tax act)

The new Testo unico delle imposte sui redditi (consolidated income tax act)

The Testo unico delle imposte sui redditi was enacted by d.lgs. no. 117 of 19 June 2026 and applies from 1 January 2027. What changes, from when, and how to prepare.

The Testo unico delle disposizioni legislative in materia di imposte sui redditi was enacted by d.lgs. no. 117 of 19 June 2026 (G.U. no. 152 of 3 July 2026, S.O. no. 26), implementing the delegation contained in art. 21, paragraph 1, of law no. 111 of 9 August 2023. The decree has been in force since 4 July 2026, but its provisions apply from 1 January 2027 (art. 377): until then, d.P.R. no. 917 of 22 December 1986 (TUIR) remains applicable.

What changes (and what does not)

The delegation does not authorise a purely formal reordering: art. 21, paragraph 1, letter b), of law 111/2023 calls for the rules in force to be coordinated “in formal and substantive terms […] making the necessary amendments”, and letter c) for the express repeal of provisions that are incompatible or no longer current. The recodification is therefore predominantly systematic — merging provisions, coordination, repeal of superseded provisions — but it does not leave everything unchanged: individual provisions have to be compared, not assumed to be identical.

For the taxpayer the most immediate practical consequence is the renumbering of articles and paragraphs. Until 31 December 2026 nothing changes: returns, deeds and written submissions continue to cite the articles of the TUIR. From 1 January 2027 articles 1 to 191 of d.P.R. 917/1986 are repealed (art. 376, paragraph 1, letter e, of d.lgs. 117/2026), and references to those provisions contained in other rules or in measures are to be understood as made to the corresponding provisions of the testo unico, as indicated in each article (art. 376, paragraph 2).

The concordance, moreover, does not have to be looked for elsewhere: the articles of the testo unico set out, beneath the heading and before the first paragraph, the earlier provision from which they derive — for art. 1, “articolo 1 decreto del Presidente della Repubblica 22 dicembre 1986, n. 917”. The closing articles of a technical character, such as 376 and 377, do not carry that indication.

A system-wide date: 1 January 2027

The income tax testo unico does not stand alone: 1 January 2027 is the date common to the whole reorganisation. The VAT testo unico (d.lgs. no. 10 of 19 January 2026, art. 171) and the testo unico on compliance obligations and assessment (d.lgs. no. 141 of 5 August 2026, art. 368) apply from that same date, a commencement they carry in their own original text. To these are added five earlier consolidated acts, whose commencement was deferred from 2026 to 2027 by art. 4 of decree-law no. 200 of 31 December 2025, converted with amendments by law no. 26 of 27 February 2026: administrative and criminal tax penalties (d.lgs. no. 173 of 5 November 2024), minor state taxes (d.lgs. no. 174 of 5 November 2024), tax justice (d.lgs. no. 175 of 14 November 2024), payments and collection (d.lgs. no. 33 of 24 March 2025) and registration tax and other indirect taxes (d.lgs. no. 123 of 1 August 2025). D.lgs. 141/2026 also contains the coordinating and corrective provisions on the consolidated acts already enacted: with effect from 7 August 2026 it amended art. 376 of the income tax testo unico itself.

The practical safeguard

What to do, and when. Up to the end of 2026: no action on documents already under way; continue to cite d.P.R. 917/1986. In the last quarter of 2026: map the references to the TUIR contained in articles of association, contracts, expert reports, the firm’s forms and management software, setting the new location alongside each one. From 1 January 2027: cite the testo unico in new documents; in documents concerning earlier tax periods, continue to cite the provision then in force, giving the corresponding provision of the testo unico in brackets. It is worth keeping the concordance table used and the date on which it was checked on Normattiva. The firm will progressively update its guides and forms to the recodified references.

The consolidated acts are not the end of the line: art. 21, paragraph 2, of law 111/2023 delegates to the Government the restructuring of tax law provisions into a code divided into a general part, with a single body of rules for the concepts common to all taxes, and a special part, with the rules for each individual tax. The deadline for implementation is twelve months from the entry into force of the last of the legislative decrees referred to in art. 1, paragraph 6, of the same law.

• Law no. 111 of 9 August 2023, art. 21 — the delegation for reorganisation by way of consolidated acts (deadline: 31 December 2026) and for the code of tax law; text in force on Normattiva.
• D.lgs. no. 117 of 19 June 2026 — Testo unico delle disposizioni legislative in materia di imposte sui redditi (G.U. no. 152 of 3 July 2026, S.O. no. 26); in particular art. 376 (repeals) and art. 377 (commencement).
• The TUIR — d.P.R. no. 917 of 22 December 1986: articles 1 to 191 repealed with effect from 1 January 2027; text in force on Normattiva.
• Decree-law no. 200 of 31 December 2025, converted with amendments by law no. 26 of 27 February 2026, art. 4, paragraphs 1–5 — deferral to 1 January 2027 of the commencement of the consolidated acts under d.lgs. nos. 173, 174 and 175 of 2024 and nos. 33 and 123 of 2025.
• D.lgs. no. 10 of 19 January 2026 — Testo unico delle disposizioni legislative in materia di imposta sul valore aggiunto (G.U. no. 24 of 30 January 2026, S.O. no. 4); art. 171 (commencement).
• D.lgs. no. 141 of 5 August 2026 — approval of the Testo unico delle disposizioni legislative in materia di adempimenti e accertamento, together with coordinating and corrective provisions relating to the consolidated acts (G.U. no. 181 of 6 August 2026, S.O. no. 28); art. 368 (commencement).