Nainggolan has signed a four-year deal with an Inter side preparing for their first appearance in the Champions League since the 2011-12 campaign, while Davide Santon and Nicolo Zaniolo have gone the other way.
Nainggolan, who retired from international football in May after being overlooked for the World Cup, has joined Inter for an initial fee of 38million euros (£33.5m), Roma have announced.
Former Newcastle full-back Santon has moved for 9.5m euros (£8.4m) while the Giallorossi have paid 4.5m euros (£4m) for 18-year-old midfielder Zaniolo.
Inter Milan sporting director Piero Ausilio told his club’s website: “The Belgian is a real coup for Inter. He is an important player and one that has always been decisive, particularly during his years with the Giallorossi. He is a top player.”
