Hans Fredrik Neij, Gottfrid Svartholm Warg, Peter Sunde and Carl Lundström are accused of 33 cases of alleged copyright infringement.
The trial will last 13 days, public prosecutor Håkan Roswall told The Local.
As organizers of the site, the defendants are “promoting other people's infringements of copyright laws," according to charges filed by Roswall in January 2008.
Roswall declined to comment on the case while it is still ongoing but when charges were filed he called for the four to pay damages of 1.2 million kronor ($185,000) to the Swedish state.
The Pirate Bay is a bittorrent tracker which allows users to download files from Pirate Bay's indexed search engine – enabling movies, music, games and software to be downloaded and shared among users for free.
"It's not merely a search engine. It's an active part of an action that aims at, and also leads to, making copyright protected material available," Roswall told Reuters in January 2008.
The Pirate Bay argue on their web site that, “only torrent files are saved at the server. That means no copyrighted and or illegal materials are stored by us. It is therefore not possible to hold the people behind The Pirate Bay responsible for the material that is being spread using the tracker.”
Defendant Sunde was defiant when he told Reuters, "it's idiotic. There is no legal ground (for the charges)."
Premises connected to The Pirate Bay were first raided in 2006. The complexity of the case led to delays in charges being filed and the case being bought to court.
The site is also facing sizable compensation claims from record companies and the Motion Picture Association of the United States.
"The record companies can go screw themselves," said Pirate Bay founder Gottfrid Svartholm Warg to The Local on learning of the claims in March 2008.
The Pirate Bay is ranked as the 109th most popular web site on the internet by web information company Alexa.
The four defendants have run the site since 2004 after it was started in 2003 by the Swedish anti-copyright organization Piratbyrån.
Revenue is made from advertisers as members are not charged to use the site.
Stay tuned to The Local for comprehensive coverage of the trial. And brush up on the background to the case with a look through our archived articles on The Pirate Bay.