The money-laundering charges allege 42 million ringgit stemming from illegal activities was transferred to Najib's bank accounts between December 2014 and February 2015.
As the charges were read out in a packed courtroom in Kuala Lumpur, Razak responded: "I understand".
The 65-year-old was arrested last month and now faces up to 15-years in jail.
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The prosecution team, led by Datuk Mohamad Hanafiah Zakaria, applied to have it heard together with the previous charges before another High Court.
He and his wife, Rosmah Mansor, have been barred from leaving the country since he lost an election in May, and the new prime minister, his mentor-turned-foe Mahathir Mohamad, relaunched an investigation into 1MDB.
The yacht which was seized by Indonesian authorities previous year, was purchased by Malaysian financier Jho Low in 2014, a close family friend of Najib.
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Investigations into 1MDB have been moving swiftly. That time he pleaded not guilty to the charges and was released on bail.
Then the Wall Street Journal reported it had seen a paper trail that allegedly traced close to $700m from the fund to Mr Najib's personal bank accounts.
SRC International was a subsidiary of 1Malaysia Development Berhad (1MDB).
SRC, created in 2011 by Najib's government to pursue overseas investment in energy resources, was a unit of 1MDB until it was moved to the finance ministry in 2012.
Following Najib's election loss, police seized a vast trove of items - including expensive handbags and jewellery - from properties linked to him with an estimated value of up to $273 million.
On Tuesday, a luxury yacht that was allegedly procured using stolen money from 1MDB was returned to the Malaysian government.
Najib set up 1MDB when he took power in 2009 for the stated goal of promoting economic development, but the fund amassed billions in debts and is being investigated in the USA and several other countries for alleged cross-border embezzlement and money laundering.