The Eagles have agreed a €2.5 million deal for the highly rated footballer, who has put pen to paper to a five-year deal after passing a medical at Estadio da Luz.
The 20-year-old, who was also followed by a number of Spanish and Italian sides, has had a €30 million release clause inserted in his deal.
Jorge Rojas is club’s third signing for the 2013/2014 season, with Filip Djuricic and Miralem Sulejmani already accepting offers from Benfica.
The talented attacking midfielder arrives at Estadio da Luz as a replacement for Nicolas Gaitan, who looks set to leave the Eagles in the summer transfer window.
Jorge Rojas has made a total of 53 league appearances for Cerro Porteno, while he was handed his Paraguay debut in a friendly win over Guatemala in February 2012.