The raid was carried out at a weekend computer fair in Bradford and involved the seizure of counterfeit software and machinery to 'chip' games consoles.
Chipping a console makes it possible to play pirated games on it by circumventing the digital rights management systems of the machine.
Two men were arrested at the fair at the Richard Dunn Sports Centre in Bradford for selling copied computer software and games.
Police and trading standards officers then carried out a search of a home in Leeds and uncovered 5,000 discs containing pirated software, music and films.
Though the value of the pirated items was estimated by trading standards officials to be £100,000, the value of that number of geniune products would have been £1 million, said the West Yorkshire Trading Standards Service (WYTSS).
"The Service would like to send out a warning to individuals involved in software piracy that they will be dealt with severely," said Graham Hebblethwaite, chief officer of the WYTSS.
"The maximum penalty for crimes under copyright and trademark legislation carries a sentence of ten years imprisonment.”
“The illegal software trade is worth hundreds of millions of pounds in the domestic market alone," he said.
"Trading Standards have had the power to enforce the Copyright, Designs and Patents Act since April 2007 and the Service is committed to enforcing this Act to eradicate the sale of counterfeit software, music and computer games in the county."
Last year a section of the Criminal Justice and Public Order Act was put into force, changing the Copyright, Designs and Patents Act to give new powers to trading standards officers.
They were given the power to seize goods and documents and make test purchases. They also have a general duty to enforce copyright law.
The move was one of the recommendations of the Gowers Review of Intellectual Property carried out on behalf of the Treasury by Andrew Gowers in 2006.
The then-Department of Trade and Industry backed the move with what it said was £5 million of new investment in the trading standards system.