The monastery of San Francisco, which was constructed in the first half of the fourteenth century, has a church called San Francisco de Oporto.

The structure is made of granite and combines Gothic and Romanesque characteristics. The baroque portico was constructed between the 17th and 18th century.

The enmity that the then-bishop of Porto, Dom Pedro Salvadores, displayed toward the Franciscan Order for many years, even going so far as to banish them from the city, made it extremely difficult for the Franciscans to settle in the city after they arrived there in 1233. Thanks to the intervention of Pope Innocent V, who, through the bull Doelentis accepimus, confirmed the Franciscan order's sovereignty of the property, the Franciscan friars were given permission to construct the initial church of the monastery of San Francisco in 1245. With a lot of public backing, the current church's construction started in 1383 and was finished in 1410.

Thanks to the contributions of the families of Oporto who built their pantheons in the church's enclosure over a period of around 160 years between the 16th and 17th century, the inside of the church was covered in wood by Portuguese image-makers, giving it its current appearance.

The uncertain political climate in the nation during the 19th century caused significant harm to the church. The structure was utilised as a stable in 1809, when Napoleonic troops were occupying Portugal, which resulted in damage to several of the church's altarpieces and other decorative items like columns. The monastery was demolished during the Portuguese Civil War (1828–1834), leaving just the church standing. Franciscan Order members were exiled from the nation by King Pedro IV's decree following the war's conclusion because they had sided with King Miguel I, Pedro IV's rival. The convent's original location was used to construct the current Palacio de la Bolsa.

It was designated a National Monument in 1910. The church was included in the Porto, Portugal, old town's monumental ensemble when it was added to the World Heritage List in 1996.

The outstanding specimen of Gothic architecture in Porto, the church's structure has not seen significant changes since 1410.

The newly constructed church, which had three naves in five bays, a projecting transept, and a tripartite chancel with buttresses, significantly increased the size of the previous structure. It was finished in 1410. Two staggered buttresses reinforce the main façade (the same solution is used to reinforce the transept, apse and apsidal apses).

The planimetric model chosen is comparable to one that has been successfully used in numerous Portuguese churches since the Mendicant Gothic of the 12th century. The presence of lacrimal themes with sphere-decorated decorations in the upper portion of the main chapel, which have Galician influences, is a significant regional feature.

A rose window with twelve pieces is divided into twelve sections on the main façade by radial columns connected by arches. The baroque altarpiece for the portal-frontispiece was added in the 18th century. It has two levels, the first of which is flanked by twin Solomonic columns, and the second of which contains a niche with an image of San Francisco and is surrounded by corbels and Solomonic columns.

A cornice rests on corbels along the south façade, which faces the Duero River. A relatively plain doorway with three pointed archivolts can be found on this façade. Reliefs in the Mudejar style are used to embellish the internal mouldings. A pentagram-decorated gable over the doorway is present.

Another pentagram may be found on the rear façade, above the altar, and is framed by a little rose window with tracery around it.

The current church is made up of three naves, each with five bays. The centre nave is higher than the side naves and features a wooden coffered ceiling with a gabled design. The ten bays of pointed arches that make up the naves are supported by fasciated columns with zoomorphic and phytomorphic capitals; four of these columns define the choir loft. As already indicated, the chancel is tripartite, and the transept is projecting and lavishly lighted. The massive buttresses that surround the high altar are deeper. Only the window on the south side of the transept receives light because the one on the north side was obstructed when the Palacio de la Bolsa was built. The central nave and transept's ceiling panelling were installed in 1732.

A statue of St. Francis of Assisi from the 13th century is the only piece of artwork from the original church that has survived. One of the earliest preserved mural paintings in the nation, credited to Antonio Florentim, was painted during the reign of D. Juan I and depicts Our Lady of the Rose. An altarpiece from 1740 presently frames the group.

The Chapel of Our Lady of the Conception, also known as the Tree of Jesse, is a carving by Antonio Gomes and Filipe da Silva that is located on the left side of the church. It is a revision of an earlier work that was created between 1718 and 1721. The statues created by the Bracarense sculptor Manuel Carneiro Ado in 1719 are the most notable of the earlier work. It is a multicoloured engraving that shows the family tree of Jesus, with twelve Judah kings connected to Jesse's reclining body by the tree's branches. Joseph is positioned beneath a picture of the Virgin and Child at the top of the tree. The statues of Saint Joachim and Saint Anne, Mary's father and mother, as well as four Franciscan doctors who wrote about the Immaculate Conception, can be found in the niches that surround the ensemble.

The Portuguese Johannine Baroque reached its peak in the 1750s, and works from this era with Rococo influences may be found in the cathedral. The altarpiece of the Annunciation and the altarpiece honouring the Moroccan Franciscan martyr saints are two examples. José Teixeira Guimares and Francisco Pereira Campanha were responsible for the addition of new components to the church between 1760 and 1773. These altarpieces include those of the Virgin of Solitude, the Virgin of the Annunciation, and Saint John the Baptist in the Carneiros chapel in the transept.

The secretariat and office of the order in Oporto were housed under the catacombs of the church of San Francisco, which were constructed beneath the house belonging to the church between 1746 and 1749. Two more construction phases were added after the initial one. In 1795, architects Antonio Pinto Miranda and Vicente Mazzonneschi added a substructure beneath the church. The floor beneath the church of San Antonio was covered by the second addition, which was completed in 1802.

The patrons of the Order in Porto and their families were buried here between 1749 and 1866. Based on Minister Costa Cabral's Public Health Law, the burials were stopped in 1866. The burials in the cemetery belonged to all the brothers, with the exception of the oldest brothers, according to the statute from 1751. The brothers started to be interred in a separate section of the Agramonte municipal cemetery starting in 1866.