This basilica falls within the peninsular group considered by Palol as typical of the Mediterranean coast, including the Balearic Islands, which is very common in Syria and also widespread in North Africa. Three phases of construction can be distinguished in the building as a whole: the first phase in which the basilica was built; the second phase in which the baptistery is added, with a baptismal pool on ground level in the shape of a Greek cross; and the third phase, in which what changes is the baptismal pool, which becomes circular in shape and is raised from the ground and in which the arms of a cross are barely indicated by lobes.
It is of a uniform design: Basilica and tripartite sanctuary closed to the outside by a single straight wall. The naves are separated by columns. The altar is in front of the apse and is surrounded by gates and in the apse is the chancel bench.
The Basilica of Gerena was also used as a necropolis, most of the tombs being in the main nave.
The structure found in the excavations has a rectangular floor plan, oriented E-W, with three naves and a flat tripartite sanctuary. It has a central apse and two side apses. The baptistery is located at the foot of the church, with the baptismal pool in the centre.
The whole ensemble is 24.30 metres long (baptistery included) by 9.30 metres wide, the length of the basilica without the baptistery being 18.40 metres.
Of the church only the foundations remain. They are perfectly interlocked and built on a base of calcareous rock that has been levelled due to the slope of the ground in a N-S direction.
The foundations are of two types: the exterior ones, made with fragmented bricks, broken tiles and stones, and the interior ones, in which masonry predominates, with the occasional inclusion of bricks and tiles, bound together with mortar as in the external walls. They are built on a base of calcareous rock that has been levelled due to the slope of the ground in a N-S direction.
They are very regular in width, measuring 0.76 to 0.80 metres, except in the sanctuary, where the width ranges from 0.9 to 1 metre.
The building has a very regular, symmetrical layout arranged along a longitudinal axis. The apse is 2.50 metres long by 3.40 metres wide and the pastophoria 1.50 metres wide by 2.70 metres long. The central nave is interrupted to the west by a transverse wall that creates a small rectangular space at its feet, measuring 3.30 metres by 1.54 metres.
In the foundations that separate the north nave from the central nave, there is a small circular hole that could be the seat of a column, with a diameter of about 0.60 metres and separated from the transverse wall of the sanctuary by 2.20 metres.
The side naves are 1.50 metres wide and 16.70 metres long. At the foot of the north nave, a 0.70 long and 0.23 metre high slab of paralepipedic granite has appeared, and is associated with a possible door, a hypothesis corroborated by the signs of wear it shows, presumably due to continuous treading, as well as the fact that it has a small hole (possibly for a hinge) and another rectangular one (to fit the frame).
There are hardly any remains of the floor, only a small surface of "opus signinum". The baptistery, at the foot, measuring 5.90 x 9.30 metres, must have been annexed to the church because it is not connected to the foundations of the latter, its foundations being 0.80 to 0.90 metres wide. On the southern side a footing appeared, on the same axis as the wall of the basilica. Again, the little pavement that has appeared is in "opus signinum".
On the axis of the basilica appears the baptismal pool. The eastern side of the enclosure is separated from the basilica by a limestone ashlar with traces of mortar. On the pavement, there is also an interruption, parallel to the wall of the basilica, which could indicate the existence of another higher wall or construction, leaving a narrow corridor between the basilica and the baptistery, possibly to allow access from this side without passing through the baptismal hall.