The church has a massive, stucco-cement Neo-Classic and Baroque facade with no openings and flanked by 2 almost square twin bell towers.  The simple arched main entrance, flanked by two pilasters, has a rectangular window above it flanked by two small occoli decorated along the outer edges.  Above it is a small niche. A wooden tablet, carved with the Spanish coat-of-arms, is above the main door.  The quaint Moorish-inspired belfries have 2 levels, topped by balustrades, with one semicircular blind opening at the second level.

The church houses the miraculous 17th century, life-size crucifix of the Black Nazarene or Santo Cristo de Sinait.

According to a long-lost manuscript, written between 1731 and 1734, this crucifix was found by some Sinait fishermen in 1620 floating along the coast of Sitio Lugao, Dadalaquitan Norte, in a casket together with the image of La Virgen Milagrosa de Badoc and was immediately placed inside the church.

Carved in hardwood and 18 feet long, it has a rich brown color and an impressive countenance. The sanctuary became famous throughout the Ilocos and devotion to the image was tirelessly spread in 1754 by Father Juan Dominguez.  It is believed to have aborted a plague that hit Vigan in 1756 and according to residents, still perspires sweet-scented oil.  A replica was recently installed by parish priest, Fr. Raymundo Garcia, at the spot where the statue was supposedly found