Santi Marco Evangelista e Pio X is a modern parish church at Via di Casal Selce 271 in the small locality of Pantan Monastero in the district of Casalotti and south-west of the suburb of Casalotti.
This church is in the municipality of Rome, but belongs to the diocese of Porto Santa Rufina.
It is a plain neo-Romanesque building on a rectangular plan with a pitched and tiled roof, having a short presbyterium reaching a lower elevation and having a semi-circular apse. There are no nave aisles. The exterior walls are rendered in a pale orange-yellow, with brick pilasters occupying the corners and dividing the five bays of the nave. There are five nave windows, alternately rectangular and round-headed with three of the latter and two of the former.
The entrance façade has an external loggia, of dark grey stonework and having three open arches in front with one more on either side. These arches have no imposts. The loggia is slightly wider than the nave behind, and the tiled roof is hipped as well as having an upward slope. Above the loggia there is a round window with a suburst fenestration, in a dished brick frame formed by three courses stepping inwards. There is no other decoration, apart from a metal Greek cross in the gable.
The ancillary buildings to the left have a cloistered walkway with arches facing the street, connecting to the loggia. There is also an impressive detached campanile, much more architecturally dignified than the church. It is a tower on a square plan, with five storeys below the bellchamber. The corners are occupied by thin concrete pilasters which provide the frame of the edifice. Each face of the tower has four outer vertical courses of red brick blocks, each course one block wide, and two inner ones in yellow brick. These are laid so as to recess inwards. The central vertical zone of each face is open, apart from the concrete floors of each storey. The bellchamber is pyramidal, with a large gabled sound-hole on each side in the form of a trapezoid. These sound-holes have balustraded balconies, the balustrading being in the form of a repeated cross within a circle.