---
kind: "section"
citation: "26 U.S.C. § 645"
title: "26"
title_heading: "Internal Revenue Code"
number: "645"
heading: "Certain revocable trusts treated as part of estate"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/26/645"
units:
  - "Subtitle A — Income Taxes"
  - "Chapter 1 — Normal Taxes and Surtaxes"
  - "Subchapter J — Estates, Trusts, Beneficiaries, and Decedents"
  - "Part I — Estates, Trusts, and Beneficiaries"
  - "Subpart A — General Rules for Taxation of Estates and Trusts"
---

# §645. Certain revocable trusts treated as part of estate

- (a) **General rule—** For purposes of this subtitle, if both the executor (if any) of an [estate](/usc/26/1361.md?p=c-3) and the trustee of a qualified revocable trust elect the treatment provided in this section, such trust shall be treated and taxed as part of such [estate](/usc/26/1361.md?p=c-3) (and not as a separate trust) for all taxable years of the [estate](/usc/26/1361.md?p=c-3) ending after the date of the decedent’s death and before the [applicable date](/usc/26/1361.md?p=c-1-B-iii).
- (b) **Definitions—** For purposes of [subsection (a)](#a)—
  - (1) **Qualified revocable trust—** The term “qualified revocable trust” means any trust (or portion thereof) which was treated under [section 676](/usc/26/676.md) as owned by the decedent of the [estate](/usc/26/1361.md?p=c-3) referred to in [subsection (a)](#a) by reason of a power in the grantor (determined without regard to [section 672(e)](/usc/26/672.md?p=e)).
  - (2) **Applicable date—** The term “[applicable date](/usc/26/1361.md?p=c-1-B-iii)” means—
    - (A) if no return of tax imposed by [chapter 11](/usc/26/chstB/ch11.md) is required to be filed, the date which is 2 years after the date of the decedent’s death, and
    - (B) if such a return is required to be filed, the date which is 6 months after the date of the final [determination](/usc/26/1313.md?p=a) of the liability for tax imposed by chapter 11.
- (c) **Election—** The election under [subsection (a)](#a) shall be made not later than the time prescribed for filing the return of tax imposed by this chapter for the first taxable year of the [estate](/usc/26/1361.md?p=c-3) (determined with regard to extensions) and, once made, shall be irrevocable.

## Source credit

(Added Pub. L. 105–34, title XIII, § 1305(a), Aug. 5, 1997, 111 Stat. 1040, § 646; renumbered § 645, Pub. L. 105–206, title VI, § 6013(a)(1), July 22, 1998, 112 Stat. 819.)

## Notes

### Editorial Notes

### Prior Provisions

A prior section 645 was renumbered section 644 of this title.

### Amendments

1998—Pub. L. 105–206 renumbered section 646 of this title as this section.

### Statutory Notes and Related Subsidiaries

### Effective Date

Pub. L. 105–34, title XIII, § 1305(d), Aug. 5, 1997, 111 Stat. 1041, provided that: “The amendments made by this section [enacting this section and amending section 2652 of this title] shall apply with respect to estates of decedents dying after the date of the enactment of this Act [Aug. 5, 1997].”