This chapel is located in Wied il-Għasel, limits of Naxxar. It is a late medieval chapel composed of a single chamber, with an east-end aspe having an altar and a west-facing door. The roof is slightly pitched. The façade consists of a small arched door with a small round window above and an eroded coat of arms on each side. Between the door and window is a small plaque with a Latin inscription. This chapel still has a small marble inscription: non gode l' immunita' ecclesiastica which were placed at all churches and chapels negating the right for lawbreakers to seek protection from the authorities if they hide in churches. A bell cot on the roof was a later addition. On the left of the door is a small hole in the wall from which oil and produce were once donated by farmers and passers by to support the chapel's needs. The east-end wall around the altar has polychromed mural decorations with roundels containing saints which were whitewashed over at an unknown period. Unfortunately, in the early 1990s, while scraping off the whitewash to for repainting parts of the murals, decorations were also damaged unknowingly, but later works progressed in a way that the remaining parts of the murals were cleaned and restored professionally and saved for the enjoyment of all.

Recently, the chapel was restored and the door was recently changed to a metal one for security purposes and the six deteriorated stone waterspouts were replaced by new ones. The chapel has a parvis at front surrounded with a low stone wall. The chapel also has graffiti on its external walls dated to 1766, 1795 and 1897.

Mepa scheduled St Catherine's chapel in Naxxar as a Grade 1 national monument as per Government Notice number 628/08 in the Government Gazette dated July 12, 2008.