Gates is also admitting to carrying out a vast scheme to hide millions of dollars in foreign bank accounts on Manafort's behalf.
Prosecutors are trying to craft a narrative through the various vendors, bookkeepers, and accountants who have testified that Manafort, through Gates, directed his own illicit transactions.
In stunning testimony at Manafort's trial on tax and fraud charges, Gates stated he and Manafort had 15 foreign accounts they did not report to the federal government, and knew it was illegal.
Gates said that he did all of those crimes "at the direction of Mr. Manafort", CNN reported.
Gates, 46, is already facing up to five years in prison under the terms of a plea deal he struck with prosecutors in February when he pleaded guilty to two charges of conspiracy and lying to the Federal Bureau of Investigation. Lawyers then met privately with the judge for a bench conference.
During opening arguments last week, the defense team made it clear they intend to blame Gates, who handled some day-to-day business operations for Manafort, for numerous alleged reporting deficiencies Manafort is charged with.
Citan a Álvaro Uribe para septiembre
Por su parte, Macias , presidente del Congreso anunció que le devolvera la carta a Uribe . Y, en esa decisión, la corte también compulsó copias para investigar al expresidente.
Prosecutors said last week that they meant to call him to the stand before resting their case this week.
Attorney Thomas Zehnle accused Gates of embezzling money from Manafort's consulting firm and said that Gates was now agreeing to cooperate with prosecutors to cover his tracks.
Gates has been cooperating with special counsel Robert Mueller's Russian Federation probe after he cut a plea deal earlier this year.
Ahead of Manafort's trial, Mueller's prosecutors listed Gates as a potential witness, indicating that he was expected to play a central role in the prosecutor's case against his former boss.
The most critical moment in the financial fraud trial of former Trump campaign chairman Paul Manafort will likely arrive this week with the testimony of his "right-hand man" - the person defense attorneys blame for any crimes.
The Manafort trial marks the first major court test for the Mueller investigation.
While Gates already pleaded guilty to charges of conspiracy against the United States and lying to the FBI, Monday's testimony marked his first time stating he committed crimes with another former Trump associate.