A statement released by the U.S. Department of Justice announced feds would conduct the autopsy, which was requested by Brown's family.
"Due to the extraordinary circumstances involved in this case and at the request of the Brown family, Attorney General Holder has instructed Justice Department officials to arrange for an additional autopsy to be performed by a federal medical examiner. This independent examination will take place as soon as possible," the statement said.
The first autopsy was conducted by the state of Missouri and the justice department release said it would take that investigation into account.
"Even after it is complete, Justice Department officials still plan to take the state-performed autopsy into account in the course of their investigation," the release said.
The announcement came after a night of violence and protests in Ferguson.
Brown was shot to death Aug. 9 by St. Louis County Police officer Darren Wilson. Some witnesses said they observed the unarmed teen holding his hands above his head when he was shot.
The incident has sparked riots and criticisms about alleged police brutality and racism.