Under Iowa law, if you have been convicted of what is known as an "infamous crime" (including felonies and possibly aggravated misdemeanors), you lose the right to vote, but you may regain this right by (1) completing your sentence (including any term of probation, parole, or supervised release) and (2) having your right to vote restored by the governor.
If you complete the terms of your sentence after July 4, 2005, the Department of Corrections will send your name to the governor, who will consider whether your right to vote should be restored. If your right to vote is restored, you will receive a restoration of citizenship certificate in the mail at your last known address, which you should present when you register to vote.
If you completed your sentence before July 4, 2005, your right to vote was restored automatically by former Governor Vilsack, through Executive Order 42. The executive order is proof that your right to vote was restored, and you may need to show it when you register. A copy of it is available here.
Whether your right to vote was restored before or after July 4, 2005, you must register or re-register to vote.
For more information, visit the Governor's Office's website on restoration of voting rights
or call them at 515-281-5211.