Nostra Signora del Pilar dei Marianisti is a mid 20th century convent and public chapel at Via Latina 22, in the Appio Latino quarter.
The chapel is attached to the Generalate (world headquarters) of the Society of Mary (Marianists).
The chapel is also a public Mass centre of the parish of Santa Caterina da Siena a Via Populonia.
The chapel is an integral part of the convent building, which is a single wing arranged on the plan of three sides of a hexagon. The chapel occupies most of the right hand wing, and stands over a crypt.
There is no façade because it abuts onto the convent at its near end, but there is a little entrance lobby accessed by a flight of steps. The nave has four bays, followed by a narrower sanctuary with an integral apse of the same height. All of these are covered by one flat roof, bounded by a low brick parapet above a stone cornice.
The fabric is in red brick, with footings in limestone. Each nave bay has a long vertical rectangular window, topped by a fragment of floating cornice above which is a small round window. The sanctuary has three small vertical windows just below its roofline, near the junction with the nave.
The sanctuary and apse has ancillary accommodation wrapped around their lower elevation.
For the time being (parish website, July 2018), public Mass is being celebrated here at 9:00 on Sundays and Solemnities.
Now that the new parish church of Santa Caterina da Siena a Via Populonia has been constructed nearby (2013) this Mass is arguably pastorally redundant.