San Tarcisio is a modern parish church at Largo Padre Leonardo Bello 12 in the suburb of Quarto Miglio on the Via Appia Nuova, in the Appio Pignatelli district.
The dedication is to St Tarcisius.
There is a nave and side aisles on a simple rectangular plan, the walls being rendered in a very light grey.
The entrance façade of the nave is actually recessed within the side walls and pitched roof for over a metre. What would normally be an exterior porch occupying the length of the façade, with a sloping tiled roof and supported by two square concrete pillars, is actually within the side walls. Above this is an almost square stained glass window, and there is a pair of small square windows flanking the entrance. The roof gable is supported by large triangular wooden struts. The nave façade is painted a light pink, except for a white rectangle around the main window. The aisle ends are just walls with a door each, and there is a low campanile at the other end of the church.
The interior decoration reflects the fact that the founders of the parish were Franciscans, although it is now administered by diocesan clergy. The stained glass window depicts St Tarsicius, who was a 3rd century Roman martyr killed while defending the Blessed Sacrament from profanation. The four evangelists are on the apse archway, and the apse itself contains a fresco of St Tarsicius. The Blessed Sacrament chapel has wall frescoes of Our Lady and Franciscan saints.