The couple were arrested last fall in Santa Barbara on suspicion of illegally squatting in a home they once owned.
Once they were freed from jail, the Quaids fled to Canada and were granted residency in the country earlier this year.
The Santa Barbara district attorney's office later filed an extradition request to force Randy and Evi Quaid to return to the US, but the Department of Justice announced that it will not pursue the matter any further.
Joyce Dudley, Santa Barbara's district attorney, reacted to the DOJ's ruling by saying: "In declining to seek extradition, the USDOJ noted the resource intensive and lengthy process involved in seeking extradition from Canada. They further stated that extradition is generally reserved for more serious offences."
However, the Quaids "will be arrested" should they decide to return to the US, Dudley warned.
Randy previously claimed that he and wife Evi are the targets of a Hollywood conspiracy to kill them, even presenting his case in a docu-drama titled Star Whackers.
The actor is perhaps most widely known for playing Cousin Eddie in the National Lampoon's Vacation film franchise.
> Dennis Quaid 'supports' troubled brother Randy
Watch Randy Quaid discuss the alleged 'Star Whackers' conspiracy below: