Updated October 8, 2026. Quick answer: No. Illinois is a common law state. At divorce, 750 ILCS 5/503 has the court “divide the marital property without regard to marital misconduct in just proportions”, and at death a surviving spouse can renounce the will for a fixed share. The IRS lists nine community property states.
Illinois community property at a glance
| Item | What the documents say |
|---|---|
| Regime | Common law |
| At divorce | The court divides marital property in just proportions (750 ILCS 5/503) |
| At a spouse’s death | A spouse who renounces the will takes one-third of the entire estate if there is a descendant, one-half if none (755 ILCS 5/2-8) |
| Federal basis at the first death | A qualified joint interest between spouses: one-half is included in the estate and steps up |
| Source | Illinois General Assembly; IRS Publications 551 and 555; 26 U.S.C. 1014 |
What the Illinois statutes say
Illinois sorts property into marital and non-marital property. Section 503 defines marital property to mean “means all property, including debts and other obligations, acquired” by either spouse after the marriage, except property in the section’s list of non-marital property, such as “property acquired by gift, legacy or descent”.
At divorce in Illinois
Section 503 does not use the word equitable. The court assigns each spouse’s non-marital property to that spouse and divides the marital property in just proportions after weighing the listed factors.
At a spouse’s death in Illinois
Under 755 ILCS 5/2-8, a surviving spouse who renounces the will takes “1/3 of the entire estate if the testator leaves a descendant” or “1/2 of the entire estate if the testator leaves no descendant”, filed within seven months of the will’s admission to probate.
What it does to basis when the first spouse dies
Because Illinois is not on the IRS’s list of community property states, a couple’s basis at the first death depends on title. IRS Publication 551 says to “Include one-half of the value of a qualified joint interest” in the decedent’s gross estate, and the survivor’s basis is the cost of the survivor’s own half plus the basis in the half inherited. Property in the decedent’s name alone is different: 26 U.S.C. 1014(a) gives the heir a basis equal to the property’s fair market value at the date of the decedent’s death.
Computed illustration, not tax advice: suppose an Illinois couple paid $100,000 for shares held as a qualified joint interest, and the shares are worth $400,000 when one spouse dies. The survivor’s basis is the total of two halves: $200,000 for the half that steps up plus $50,000 as the cost of the survivor’s own half, which makes $250,000. A sale at $400,000 would then show a gain of $150,000. In a community property state the same facts would give a basis of the whole $400,000. CMG’s common law step-up page goes through the difference.
What the documents do not say
- The intestate share statute, 755 ILCS 5/2-1, was not read.
Common mistakes
- Treating an inheritance as marital property; section 503 lists property acquired by gift, legacy or descent as non-marital.
- Assuming the answer in this state settles it for a couple who move; the rules depend on the state where the spouses are domiciled and, for property in a trust, on the trust.
Related: community property states by state, why only half steps up in a common law state, Illinois retirement taxes, and Illinois probate cost.
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Answer againSources
- Sec. 503 Disposition of property and debts, Illinois Marriage and Dissolution of Marriage Act (750 ILCS 5): https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=075000050K503
- Sec. 2-8 Renunciation of will by spouse, Probate Act of 1975 (755 ILCS 5): https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=075500050K2-8
- IRS Publication 551, Basis of Assets (December 2025): https://www.irs.gov/pub/irs-pdf/p551.pdf
- 26 U.S.C. 1014, Basis of property acquired from a decedent (United States Code, 2024 Edition): https://www.govinfo.gov/link/uscode/26/1014?link-type=html
Sources: the primary documents linked above, read on October 8, 2026. General information, not tax advice. Your own facts decide the outcome, and a tax professional or the state agency itself is the right place to confirm anything consequential.