Sources at the club confirmed to ESPN that Smalling was awoken in the middle of night in the house he shares with his wife and son as three armed men in hoods entered his house.
He was then forced at gun point to open his safe and hand over jewellery, Rolex watches and other valuables. Sources added to ESPN that the player and his family were unhurt.
Smalling called the police at 4.55 a.m. CEST (10.55 p.m. ET), who quickly arrived on the scene and are looking for the culprits.
The 31-year-old was not involved in Roma's Europa League quarterfinal second leg clash through injury, which saw them draw 1-1 with Ajax. They progress to the semifinals 3-2 on aggregate and will face Manchester United, Smalling's former side.
In November, Roma manager Paulo Fonseca had around €100,000 ($120,000) worth of valuables stolen on the eve of a clash with Fiorentina in Florence, when he and his family were not at home. That incident came just days after Lazio forward Joaquin Correa's house had been broken into.