Filing requirements and guidance

If you file a consolidated Oregon return and have more than one affiliate doing business in Oregon or with Oregon-source income, you must complete Schedule OR-AF and submit it with your return.

Select a topic to get more tax information:

Revised 2018 instructions for Forms OR-20 and OR-20-INC

On August 20, 2019, we posted revised tax year 2018 instructions for Forms OR-20 and OR-20-INC. The revisions explain recent legislation on international tax issues and how to claim Oregon modifications for GILTI, FDII, and IRC 245A. See each publication​ for complete information.

Stay current

Read the latest corporation tax topics, including federal tax reform and recent Oregon legislation.

Due dates

Oregon corporation returns are due the 15th of the month following the due date of the corresponding federal return. For example, if calendar year federal corporation returns are due April 15, the Oregon calendar year return is due May 15. If a due date falls on a weekend or state holiday, the return is due the next business day. Corporation due dates aren't affected by Emancipation Day.


The Oregon extension due date is the 15th day of the month following the federal extension’s due date. Don’t send the extension before you file your Oregon return. Include it with your return. See each publication for complete information.

Corporation tax credits


Cost of performance rule change

The 2017 Oregon Legislature decided that, starting with the 2018 tax year, corporate excise taxpayers must use market-based sourcing principles rather than cost of performance for receipts other than those from the sale of tangible personal property. We amended OAR 150-314-0435 to reflect the new market-based sourcing standard. View the previous version of OAR 150-314-0435​ for tax years prior to 2018. 

If you cannot locate the prior version of a different administrative rule, contact the department's rules coordinator.

Contact us

Phone: 503-378-4988.

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