St Lucia chapel located in Triq St Lucy Street, Mtarfa is a plain mediaeval building consisting of a single chamber with a slightly pitched roof, having an east-end apse with altar and a west-facing door.
The façade consists of a central square-headed door above which is a very small rectangular window.
To the left is another door which leads to the sacristy; this was built after the church.
At the centre of the roof is a small bell cot surmounted by a cross and has a small bronze bell. By the main door is a marble slab with the legend: Non gode imunità eclesiastica.
At front and on the left is an enclosed parvis, separated by a stone doorway. The flagstones are a relatively recent replacement. Around the chapel at the rear is a recessed ditch which avoids rainwater damaging the chapel's stone fabric.
This chapel is typical of late mediaeval chapels in Malta, of which a few have survived.
Mepa scheduled St Lucia chapel as a Grade 1 national monument as per Government Notice no. 628/08 in the Government Gazette dated July 21, 2008.