The proto-basilica cathedral of San Lorenzo, is the Catholic cathedral of Trapani, in Sicily, as well as the mother church of the diocese of the same name. It is located in the historic center of the city, along Corso Vittorio Emanuele.

The facade of the cathedral of San Lorenzo Martire is in Baroque style and has, in the lower part, a pronaos, closed by a gate in bronze and wrought iron .
The upper part of the facade, without ornament, is decorated by Ionic pilasters and has on the right, a bell tower with a spire covered by polychrome majolica.
The interior of the cathedral is a Latin cross, with three naves separated by Tuscan columns, supporting round arches.
The central nave is covered with a barrel vault, while the two sides are covered with a cross vault; on which the side chapels open, four on each side. The transept has, behind the back walls, two neoclassical altars with geometric marble decorations: the one on the right is dedicated to San Lorenzo martyr and houses the work depicting the : "Martyrdom of San Lorenzo" by the artist Giuseppe Felici ; The left one is dedicated to Saint Stephen the first martyr and houses a work depicting the "Stoning of Saint Stephen", the artist Domenico La Bruna. Of the latter is also the picture of the Eternal Father, housed inside the deep apse . In 1995 the post-conciliar marble presbytery was built by Umberto Benini Craparotta. It consists of the cubic altar, located in the apse, surmounted by the ciborium, the chair, under the triumphal arch and the ambo complex, consisting of the pulpit, the baptismal font below and the ambo.

The building once , stood in the district «Palazzo» in which the «Consulate of the Genoese Nation» resided, called «Chapel of Saint George» of 1102.
In 1280 King James II of Aragon divided the district «Palazzo» into two districts, respectively : San Francesco and San Lorenzo , because of the presence of the respective places of worship.
In 1740 the church was restored and was given the appearance that today we can admire. All this was the work of the architect Giovanni Biagio Amico. The portico, instead, was divided into three parts with bell towers and side chapels. The choir, the choir, the high altar with its tribune, the statues and angels as ornaments were also made.
At the center of the apse is the name of God in Hebrew, the organ, the baptismal font, the confessionals and the pulpit.

The complex of the works and the numerous restoration works determined in 1788 with the establishment of the «Fabbrica del Duomo».
In 1794 the interiors were adorned with some stuccoes in Greek style, elegant paintings by Don Vincenzo Manno, depicting stories of the Old Testament, the Patriarchs, the Prophets, the Acts of the Apostles and the most significant episodes of the Gospels. Other works were then commissioned to some of the most successful exponents of the Trapani art scene of the time. In 1844 his father Gregori XVI established the diocese of Trapani and the temple of San Lorenzo became a cathedral.