IL-1065: Partnership Replacement Tax Return (2025)
Illinois · Illinois DOR · Used for tax years 2025
Form IL-1065 is the 2025 Illinois Partnership Replacement Tax Return. It reports a partnership’s income or loss, Illinois income adjustments, replacement tax, withholding, and pass-through entity tax, and calculates a refund or balance due.
What you'll need
Have your partnership’s legal name, mailing address, federal employer identification number (FEIN), NAICS code, and accounting-records location ready.
You will also need:
- Federal Form 1065 and federal Schedule K information to complete the income and deduction lines.
- Partner information for Schedule B, including names, addresses, SSNs or FEINs, entity types, income shares, withholding, and credits.
- Schedule(s) K-1-P and Schedule(s) K-1-P(3) or K-1-P(4), completed before Schedule B.
- Payment amounts and credits from previous overpayments for Step 10.
Attach supporting forms and schedules when they apply. These include Schedule B, Schedule UB, Form IL-4562, Schedule 80/20, Illinois Schedule M for businesses, Schedule F, Schedule 1299-A, Schedule NB, Schedule NLD, Schedule 4255, and Form IL-477. Attach Schedule(s) K-1-P or K-1-T and Form(s) W-2G where the return requires them.
If you are paying PTE tax and annualized your income on Form IL-2220, check Step 1, Box J, and attach Form IL-2220. Investment partnerships should attach documentation supporting their status. If you completed federal Form 8886 or federal Schedule M-3, Part II, Line 10, check the applicable box and attach the federal form.
How to file
Complete the return and applicable attachments, then have a partner sign and date Step 11.
If you enclose a payment, enter the payment amount at the top of Page 1 and attach your payment and Form IL-1065-V in the space provided. Mail the return to:
ILLINOIS DEPARTMENT OF REVENUE
PO BOX 19053
SPRINGFIELD IL 62794-9053
If you do not enclose a payment, mail the return to:
ILLINOIS DEPARTMENT OF REVENUE
PO BOX 19031
SPRINGFIELD IL 62794-9031
Common mistakes
- Completing Schedule B out of order. Read its instructions and complete the required K-1 schedules first. Complete Schedule B, Section B, before Section A. The form warns that failing to follow these instructions may delay processing or lead to requests for more information.
- Using the wrong Step 6 treatment. If your Line 35 amount comes only from Illinois and you are not a unitary filer, check Line A, carry Line 35 to Line 47, and leave Lines 36 through 46 blank. Unitary filers must check Line B and complete Step 6 instead.
- Leaving required apportionment lines blank. If any portion of Line 35 comes from outside Illinois, or you are a unitary filer, complete all of Step 6. The form specifically says not to leave Lines 40 through 42 blank.
- Omitting members from Schedule B. Attach additional copies of Section B if you have more members than the page allows, and attach all Section B pages behind Section A.
- Forgetting the payment entry on Page 1. The form reminds you to enter the amount of your payment at the top of Page 1.
Questions people ask
Which tax years does the 2025 form cover?
The form is for tax years ending on or after December 31, 2025, and before December 31, 2026. If your return is not for calendar year 2025, enter your fiscal tax year on Page 1.
What replacement tax rate appears on the form?
Step 8, Line 54, multiplies net income from Line 53 by 1.5% (.015). Later lines account for investment credit recapture and investment credits.
Do investment partnerships complete Step 8?
No. The form tells investment partnerships to skip Step 8. It also provides a separate line for investment partnership withholding in Step 9, Line 59b.
Can I receive my refund by direct deposit?
Yes. Complete Line 70 with your routing number and account number, and select checking or savings.
What if this is the partnership’s final return?
Check the final-return box in Step 1 and enter the termination date. If the return is final because you sold the business, also enter the sale date and the new owner’s FEIN.