The Internal Revenue Service is looking for 555 Iowa taxpayers who have refund checks totaling $495,001 that were returned to the IRS as undeliverable. The checks, averaging $894, can be sent when taxpayers update addresses with the IRS. A check is normally returned as undeliverable when a taxpayer moves without updating an address with the U.S. Postal Service or IRS.

The "Where's My Refund?" tool at www.IRS.gov will provide the status of the refund and, in some cases, provide instructions on how to resolve delivery problems. Taxpayers can also call (800) 829-1954. In both cases, taxpayers will need their Social Security number, filing status and amount of their 2008 refund.

The IRS also encourages taxpayers to use direct deposit for tax refunds to avoid the problems of undeliverable, lost or stolen refund checks.