"FC Internazionale are delighted to welcome on board Marco Andreolli and Hugo Campagnaro. The defenders have signed contracts with Inter until 2017 and 2015 respectively," the club wrote on their website.
Argentine international Campagnaro rejoins Walter Mazzari after four years with the coach at Napoli, moving to Inter as a free agent. He played 143 games for Napoli after joining from Sampdoria in 2009.
Andreolli, who was part of Inter's youth set-up between 2003 and 2005 and made his first-team debut for the club aged 18, also joins on a free transfer from Chievo, where he made 79 league appearances.
Inter finished in ninth place in Serie A last season.