Preliminary investigations carried out inside the Ambasciatori Palace Hotel (Via V. Veneto, Rome) brought to light several rooms delimited by _opus_ _reticulatum_ and _opus_ _testaceum_ walls, with floors in _opus_ _spicatum_ , cocciopesto and black and white mosaics. Combining these archaeological remains with those discovered in the area starting from the end of the 19th century, has made it possible to reconstruct the layout of a building that can be interpreted as a horreum of the Horti Sallustiani, with construction phases dating from the first half of the 1st century AD.