The deal includes three seasons of the show and the six-part prequel.
The series will make its basic cable premiere June 26.
"Our strategy of acquiring hit shows to complement our premium original scripted series has really resonated with our audience. With its action-soaked story lines and powerful characters, Spartacus will be a dynamic addition to our schedule," Chris Regina, Syfy's senior vice president of programming, said in a statement.
"Spartacus made an indelible impact on Starz premium viewers in the United States and with audiences around the globe," said Gene George, executive vice president of worldwide distribution for Starz. "We are very pleased to strike this accord and bring the incredible tale of Spartacus to Syfy for its viewers."
The show, which initially aired 2010-13, is inspired by the actual slave of the Roman Republic who, in 73 B.C., led a slave revolt that grew to more than 120,000 fighters. The title character was originally played by the beloved, late Andy Whitfield. Following the ailing actor's departure from the series, Liam McIntyre was recast as the lead.
The ensemble also included Lucy Lawless, John Hannah, Erin Cummings, Peter Mensah and Manu Bennett.