Contact Us

To help us better serve you, let's start with the reason you're contacting us.

Please do not include personal information (like your account number or social security number). For account specific questions or application status please login to Alliant Online Banking to send us a message or call us at 800-328-1935.

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Need help immediately?

We're always available by phone




Lost or Stolen Card

Credit Card: 866-444-8529
ATM/Debit Card: 800-328-1935

International Calls



TTY/TTD: 800-328-1935

Bank Routing Number


P.O. Box for Credit Card Payments

Alliant Credit Union P.O. Box 1666 Des Plaines, IL, 60017-1666

P.O. Box for Mortgage Loan Payments

Alliant Credit Union P.O. Box 1098 Des Plaines, IL, 60017-1098

P.O. Box for Deposits and Loan Payments

Alliant Credit Union P.O. Box 2387 Des Plaines, IL, 60017-2387

Do not use old deposit tickets, loan coupons or mailing labels that indicate an address other than the address listed above. Save time & money - deposit your checks via our mobile app.

We only accept cash deposits via select ATMs. Please use our ATM locator on our mobile app or via Online Banking.
RESPA Qualified Written Request Disclaimer

You have certain rights under Federal law related to resolving errors and requesting information about the servicing of your mortgage. PURSUANT TO § 6 OF RESPA, A "QUALIFIED WRITTEN REQUEST" REGARDING THE SERVICING OF YOUR LOAN MUST BE SENT TO THIS ADDRESS: ALLIANT CREDIT UNION, ATTN: CUSTOMER RESEARCH TEAM, MS-NOE, P.O. Box 66945, Chicago, IL 60666-0945. A "qualified written request" is written correspondence, other than notice on a payment coupon or statement, which includes your name, account number, and the detailed reason(s) for the request. We will acknowledge receipt of your request within five business days of receiving it, and provide you with a full response or resolution within 30 business days of receipt.