The individuals and groups whose names Manafort demanded are ones who allegedly acted as unregistered foreign agents at his behest.
U.S. District Judge Amy Berman Jackson said special counsel Robert Mueller's team must hand over the names to Manafort's lawyers by Friday.
That is the same day Manafort is due in court on a request by Mueller to revoke his $10 million bail and jail him because of his alleged efforts to tamper with potential witnesses against him.
Manafort is accused — among other crimes — of acting as an "unregistered agent of a foreign principal," as part of his lobbying work for a pro-Russian political party in Ukraine.
Prosecutors claim Manafort also led others, "including former senior foreign politicians," to act as unregistered foreign agents for entities that included Ukraine's government.
Manafort's lawyers in April had asked for the names in order to prepare for trial in September before Jackson in federal court in Washington, D.C.
In agreeing with that request Tuesday, Jackson noted that Manafort needs to "prepare for a complex trial with a voluminous record within a relatively short period of time."
She added Manafort "should not have to be surprised at a later point by the addition of a new name or allegation."
But the judge rejected requests from Manafort's lawyers for details about other claims. Those include allegations Manafort lied to the Justice Department and caused someone else to make a false statement.
A spokesman for Mueller and Manafort's lawyers did not immediately respond to requests for comment.
Manafort, who has pleaded not guilty, is facing multiple criminal charges, including conspiracy to launder money and making false statements.
Last week, Mueller's office also accused him of trying to tamper with potential witnesses by sending them encrypted messages. Manafort's lawyers have denied that.
Manafort's associate, Rick Gates, earlier this year pleaded guilty to conspiracy against the United States and making a false statement. He is awaiting sentencing.
Manafort is scheduled to go on trial July 24 in federal court in Virginia on charges linked to the ones he faces in Washington.