EverQuest, EverQuest II, Vanguard and Pirates of the Burning Sea are all getting Steamed thanks to an agreement with Valve.
SOE's John Smedley said they're always "looking for additional ways to introduce our great catalogue", and hopes multiplayer loving Steam users will be quick on the uptake.
"Sony Online Entertainment propelled the MMO genre and PC gaming into new era with the launch of EverQuest," said Jason Holtman, director of business development at Valve.
For the first ten days being made available the games will be discounted at introductory prices.
"It's hard to think of a larger group of PC gamers interested in multiplayer games than those connecting to Steam. We've long been a leader in MMOs and this agreement will help bring our exciting content to millions of additional online gamers around the world," said John Smedley, president of Sony Online Entertainment.
Steam is fast becoming the dominant place for first and third-party games when it comes to digital distribution on the PC. It now faces off against even more rival services than ever before though like EA Store and Direct2Drive.