Antony Knight, 61, of Styles Lane, Sowerby Bridge, was jailed for three and a half years at Manchester Minshull Street Crown Court in July 2018 for operating an illegal fuel laundering plant.
Knight has now been ordered by the same court to repay the £519,749 he made from his crimes within three months.
The order was given in the court on Friday, April 26.
If Knight does not pay he will face five years in prison and still owe the money on his release.
Fraudster Knight was caught when officers visited his business Manor Oil Company Ltd, in August 2016
When HMRC officers went to the business, on Buckstones Road in Oldham, they found the laundering plant in an outbuilding.
Storage tanks, equipment and 2,500 litres of red diesel were seized from the unit.
There was also 24 tonnes of silica gel which is used to strip the government markers from the diesel.
The HMRC said that the forensic expert estimated the silica gel would be able to launder approximately one million litres of red diesel.
Laundered fuel is red diesel which has been filtered through chemicals or acids in an attempt to remove the Government markers.
The chemicals and acids remain in the fuel and damage fuel pumps in diesel cars.