Approximately 1.1 million direct payments were sent to deceased taxpayers, according to the report. In total, the government issued 130 million stimulus checks.
The GAO report looked at how the federal government allocated the $2.6 trillion coronavirus relief packages, including the CARES Act.
After Congress passed the $2.2 trillion coronavirus rescue bill in March, checks of up to $1,200 were automatically sent in most cases to people who filed income tax returns for 2018 or 2019, including some who are dead.
The GAO recommended that the Internal Revenue Service find a cost-effective way to notify ineligible recipients on how to return the money.
The IRS website addresses the issue, instructing those who receive checks from deceased relatives to return them in full unless the payment was made to joint filers. In this case, only a portion of the payment needs to be returned.
The accountability office also urged Congress to amend the Social Security Act to allow the Social Security Administration to share death data with the Treasury Department.
"While having this access would not have prevented the economic impact payments to deceased individuals based on IRS's initial legal determination regarding these payments, such access remains an important safeguard. We maintain that providing Treasury with access to SSA's full set of death records, and requiring that Treasury consistently use it, could help reduce similar types of improper payments in other circumstances," the GAO report said.