In 2004, the excavation carried out in the ancient city of Lissus (modern Lezha), revealed the ruins of a public bath house dating to the 2nd century A.D., which in the 5th century A.D., was transformed into a Christian basilica. This monument is situated in the archaeological area B, denominated after the division of the lower part of the ancient city of Lissus into two area, respectively area A and B. Although the monument was discovered in the 70s, during the archaeological season of 2004, it was re-excavated and a plan of the monument was drawn. The excavations were focused in the eastern room (Room 1) and in a narrow secsion that passes through the central and western rooms (Rooms 2 and 3). The first construction phase of the monument is represented by a wall line made of irregular stones (M 18), which dates to a later period then the surrounding wall of the city. The walls of the second phase were partially erected above M 18, and are mainly made of bricks. The building has three rectangular rooms that cover an area of 27 m². The eastern room expands on the north side in a quadrangle shape and it has an apse on the south. The outside part of the apse is made of opus reticulatum, which in this case represents a tile construction technique. Room 3 is also expanded on the north side of the monument and it has a rectangular shape. Room 1 has hypocausts heated by the praefurnium, situated on the north side of the monument. The destruction deposit dates to the second phase of construction and contains mosaic fragments made of black and white tessera covered on limestone’s remains. A drainage ceramic tube confirms the presence of a water tank in the western apse. Rooms 2 and 3 have mortar floors and in Room 3, the stratigraphy of the floor is mixed with modern remains. In a second phase of construction, this monument was transformed into a small Roman bathhouse. A coin of the roman emperor Claudius Gothicus found in the rubble of the hypocaust provides a terminus post quem of 270 A.D. for the end of the second phase of the building. The floor of Room 3 is made of irregular broken tiles that used to cover the hypocaust. A roughly constructed wall that divides room (M6) represents the third construction phase of the monument. In the later Roman Period or Early Byzantine Period this building was entirely rebuilt. A line of three squared pillars 4 m apart (M5a-c), divides the building from west to east. The pillars are associated with coarse stones - walls (M12 and M15), which have a joint foundation trench 22 in room 1. The E wall of room 1 was pierced by an apse and the gap between the north extension of room 1 and room 3 was closed at the end of the last phase of construction. The presence of an eastern apse, the rectangular ground plan replacing the complicated symmetry of the roman bath and scattered human bones in the excavated layers, are elements that demonstrate the fact that this building was turned into a Christian basilica in its last phase of construction.