The “Caseggiato delle Tabernae Finestrate” at Ostia is a Hadrianic commercial complex situated in the fourth region of the town, along the decumanus maximus. One of its main peculiarities is the fact that it was built on top of an earlier domus, something almost completely unknown to date. Several sondages dug in 1940 and 1970, revealed some of the rooms belonging to this building, unknown until then, belonging to the rear part of the house – perhaps identifiable as the triclinium, tablinium and part of the peristyle. The floor and wall decorations show the wealth of this domus and the high status of its owners. The study of archive materials and the excavation finds has shed new light on the building and added to knowledge of Republican and early Imperial Ostia.