In Pamplona's Old Quarter, there is a Catholic church called the Church of San Nicolás de Pamplona (Navarre, Spain). It is one of the five historic parishes that originally existed in Pamplona. San Saturnino, San Lorenzo, San Juan Bautista Church (Navarrera), and San Agustin are the other four. This building houses the parish church for San Nicolás.

It was constructed in the 12th century, and the Burgo Nuevo or Población de San Nicolás is the first place that is actually mentioned, in 1117. It was one of the three burghs of Pamplona that operated separately in the city during the Middle Ages up until Charles III the Noble's proclamation of the Privilege of the Union in 1423.

It was constructed next to the city's original outer wall, which followed what is now Paseo de Sarasate, with the intention of acting as a military and defensive bastion in defiance of the royal edict prohibiting residents of Navarrera and San Nicolás from erecting any kind of military structure against the burgh of San Cernin.

In reality, it was in 1222 during one of these neighbourhood invasions that the people of San Cernin destroyed and set ablaze the original Romanesque church-fortress, with many of its inhabitants seeking sanctuary inside. A new one had to be constructed and was dedicated in 1231.

Between the Plaza de San Nicolás, Calle San Miguel, and Paseo de Sarasate in the Old Quarter, this structure's substantial walls and railings, as well as the lone remaining watchtower, speak to its difficult past.

Only two entrances, the apse, and a few spots of the high wall are decorated in the Gothic style on the outside. A neo-Gothic portico, a superimposition of the parish house in exposed brick with some neo-Mudejar features, and a façade open to the promenade, a compilation of mediaeval eclecticism, are additions designed by architect ngel Goicoechea Lizarraga and built in 1888 by the Tudela-based contractor Blas Morte that conceal the remainder. It once had several towers, but currently there are just two: the larger one, which has machicolations and a Baroque brick top where the bells are located. The round other tower is smaller. José Martnez de Ubago created the battlements in 1924.

The interior has a Latin cross floor plan and is separated into three naves. The central roof is ribbed, while the side naves' roofs have pointed barrel vaults. It is a temple built in the Gothic style over a number of centuries. The presbytery and the ribbed roofs of the side naves and transept are examples of the 14th-century Gothic style, while the elevations and roofs of the side naves and part of the central wall are examples of the Proto-Gothic style.

One of the most significant Baroque organs in Pamplona may be found inside. It is a sizable instrument that was created in 1769.

In 2013, four coats of arms—one each for the historic towns of Navarrera, San Nicolás, and San Cernin, as well as the city of Pamplona—were affixed to the high walls of the main nave. The Navarrese painter and restorer Jorge Urdánoz Apeztegua applied gold and silver leaf to panels while employing the oil technique to polychrome the works. They are each 1.5 metres broad and 1.8 metres high. The author and the historian Juan José Martinena Ruiz came to an agreement on the design. On December 8 of that same year, they were blessed during the liturgy.