There are currently twenty-five churches in Busto Arsizio, including parish and auxiliary churches and a baptistery.A sign of "civitas christiana," as the former provost of St. John the Baptist, Monsignor Claudio Livetti, said:

Some of these churches, notably St. Mary of Piazza, St. John the Baptist, and St. Michael the Archangel, were built before the year one thousand. In the communal period the first rectories, later called parishes, were established. They involved the presence of a priest to whom the care of souls was entrusted and who generally resided at a pre-existing church. Busto Arsizio was subject to the parish of Olgiate Olona, but the community, on the basis of its growing economic resources, formed five "curate benefices" between the 13th and 16th centuries: three at the church of St. John the Baptist and two at the church of St. Michael the Archangel, while the church of St. Mary, located in the central square of the village, was configured as a sanctuary, without parish duties.

St. Charles Borromeo in 1583 transferred the ecclesiastical dignities of the parish (i.e., district) to Busto Arsizio, In the same year, according to the same page of the book quoted, the last of the seven towers of medieval Busto fell. and the curates of St. John and St. Michael were elevated to the rank of canons, as coadjutors of the provost in the care of souls (Busto Arsizio was therefore formally considered a single parish).

In the seventeenth century a new religious fervor led to the construction of new churches, such as St. Gregory in Camposanto (1632), Madonna in Veroncora (1639) and St. Bernardino (1665), as well as the rebuilding of the churches of St. John the Baptist (1609) and St. Michael the Archangel (1652). The eighteenth century saw the construction of Madonna in Campagna (1702), San Rocco (1706), the old church of Sacconago (1708), the church of St. Anne (1710, later the Civic Temple), and the church of St. Anthony of Padua (1717, in the territory of Borsano).

Busto remained de facto a single parish until 1906, when San Michele was also given that function.. Later, in 1928, Borsano and Sacconago were annexed to the municipality, bringing the number of parishes to four. Over the course of the twentieth century the other parishes were then formed until the present number of thirteen was reached. This was the century in which the most churches were built (as many as eleven, to which can be added that of the Friars Minor, which actually was built beginning in 1898, but finished during that century).

Throughout history, many churches have been demolished to be later rebuilt with greater capacity. Other churches, however, were demolished permanently: these include the church of Santa Croce, dating back to 1564 and formerly the seat of the confraternity of the Disciplini, which was deconsecrated in 1948 and demolished in 1972;Ferrario describes this oratory as "beautiful with sacred paintings" the Borsano church of Santa Maria dei Restagni; the Sacconago church of San Donato; that of St. Eurosia in Cascina Brughetto (built in the years 1719-1722, dedicated to the young martyr of Jaca and demolished in 1952); the chapel of St. Ambrose in Canton Santo, not far from the church of Santa Maria di Piazza.

In the case of Sacconago, the construction of the new church (1928) did not involve the demolition of the 18th-century church since land belonging to the old cemetery was used for this purpose.

The other churches currently existing in the territory of Busto Arsizio are described below: first, the Shrine of St. Mary, which constitutes the most important church in the city; second, the thirteen that are parish seats; third, the eleven that constitute subsidiary churches; and finally, the baptistery.

The parish churches were all built in the twentieth century, with the exception of the Basilica of St. John, the Provostal Church of St. Michael and Church of the Friars Minor, which was begun in 1898. These are very often places of worship built in areas of expansion of the city, or at other times modern and more spacious churches that take the place of older ones, as in the cases of the new parish churches of Sacconago and Borsano, both dedicated to the holy apostles Peter and Paul. The subsidiary churches, on the other hand, are all older: the only exception is St. Charles Borromeo, one of the three subsidiary churches of the provostry of St. Michael the Archangel. That building represents the last Catholic Christian place of worship built in the city. It was in fact consecrated in September 2000 by Cardinal Carlo Maria Martini, then archbishop of Milan.

Shrine of Santa Maria di Piazza

Erected in the city's historic center on a pre-existing church dedicated to the Virgin Mary, which in turn had replaced a chapel dating back to the time of Christianization,. the sanctuary of Santa Maria di Piazza (also known as the Sanctuary of the Blessed Virgin of Help) is an example of Renaissance architecture.

It was built in a few years between 1515 and 1522 under the guidance of Antonio da Lonate, who is said to have set the central plan, and "magistro Tomaxio ingeniero," probably Tommaso Rodari, author of the west and south portals, and perhaps of the loggia in the drum under the dome.

The central plan of the building, for which a Bramantesque design has been hypothesized, consists of a rigorous cubic volume punctuated by pilasters and surmounted by an octagonal tiburium with spires and a lantern that interprets in lighter forms the typology of the Lombard tradition.

Internally the lower square part is cut in the corners forming diagonal arches. niches and pendentives, harks back to Leonardo's studies of centrally planned churches, while the drum with archivolt niches (the crown of the twelve saints) echoes the examples of Santa Maria Incoronata di Canepanova in Pavia, Incoronata in Lodi, and the basilica of Santa Maria della Croce in Crema).

The interior decoration includes works of sculpture and paintings by Gaudenzio Ferrari (including the Last Supper, in the right altar) and Giovan Battista della Cerva and a copy of the lost Madonna delle Vittorie by Giovan Paolo Lomazzo.

An exact copy of the shrine, in reduced size, was built in the late 19th century in Crespi d'Adda.

Basilica of St. John the Baptist

The Basilica of San Giovanni Battista (one of the two patron saints of the city, along with St. Michael the Archangel) has the title of minor Roman basilica.

The present building was built between 1609 and 1635 on the site of a primitive three-aisled chapel dedicated by the Lombards to one of their patron saints. The bell tower was built between 1400 and 1418, so it appears to be older than the present church.

The facade, completed between 1699 and 1701 by Domenico Valmagini, features a lower order of Ionic double pilasters, a short prothyrum with arched pediment, copper and bronze doors, statues and bas-reliefs..

The interior, designed by architect Francesco Maria Richini, has several paintings by Busto painter Daniele Crespi, including Dead Christ with St. Dominic.

On the right side of the church is the "mortuary," a small temple whose author is unknown, built between 1689 and 1692. On the left side is a statue of Blessed Giuliana Puricelli from Busto.

The square in front of the church was created by demolishing some pre-existing buildings and using the area of the old cemetery, predating the one that was later built just outside the village, in what is now Ugo Foscolo Park.. Two other fine buildings overlook the same square: the recently restored Volonterio palace and the Varese credit.

Provostal Church of St. Michael Archangel

One of the city's main churches is that of San Michele Arcangelo, the city's patron saint,. which is also the seat of the provostry. With its bell tower dating back to the 10th century, which constitutes the oldest architectural element of the town, it is located on the northern edge of the ancient village, in an area slightly higher than the rest of the settlement existing at that time. For this reason, it is very likely that the base of the bell tower itself was one of the towers of a pre-existing fortification, within which there was probably a chapel dedicated to the saint (St. Michael the Archangel is the patron saint of the Lombards).

The first mention of the church of St. Michael dates from around 1300. Between 1652 and 1679 it was rebuilt by architect Francesco Maria Ricchino, who decided to reverse its orientation. In 1796 the facade was completed and restored between 1924 and 1925. The side walls and vault were restored in 1834. Due to the project initiated by the then provost Don Luigi Brambillasca and funding from the province of Varese chaired by Marco Reguzzoni, in 2004 the church of San Michele saw a profound restoration of the load-bearing structures, some works of art and the exterior facade. In 2007, restoration work began on the bell tower, which was completed the following year.

Various relics are kept in the church, including the entire body of the martyr St. Felix.. In the winter chapel, built in 1991, is a wooden crucifix from the mid-14th century, which is used in the Good Friday service to commemorate Jesus' passion and death on the cross.

Church of St. Edward

The foundation stone was laid on June 24, 1938, and the temple was consecrated on October 12 of the following year by Cardinal Ildefonso Schuster. Designed by two architect priests, Giuseppe Polvara and Giacomo Bettoli, the church was frescoed by Ernesto Bergagna between 1943 and 1947, the year it was made a parish church. The organ belonged to the church of Santa Maria di Piazza It has a single nave with light-colored walls and coffered ceiling and its interior contains paintings depicting seventeenth-century passion scenes from the demolished church of Santa Croce. The exterior is covered with exposed brick.

The church was consecrated in honor of the Holy Three Kings (Magi) and St. Edward the Confessor in memory of the main donor for the construction of the temple, knight of labor Edoardo Gabardi.

Despite the fact that its construction was largely financed by a Fascist, this parish played a key role during the Italian Resistance. In Busto Arsizio, as in the whole of the Altomilanese, the main promoter of the Resistance was not the Italian Communist Party, as it was in the rest of northern Italy. Here it was the formations linked to the future Christian Democracy, supported by the parishes, that carried out the clandestine activities. In particular, the warehouse of the parish of S. Edoardo was transformed into a warehouse of materials, and it was from here that, on the morning of 25 April 1945 at 6.30 a.m., the parish priest Don Ambrogio Gianotti sent out the order for the insurrection that would lead to the liberation of northern Italy.

Church of San Luigi and Blessed Giuliana

Erected in the early 1950s at the behest of the provost of St. Michael the Archangel Fr. Luigi Scola, it stands in the new neighborhood named after Blessed Giuliana Puricelli. It was opened for worship on Sept. 15, 1957,. and became a parish church the following year. The church has a rectangular plan and was built of reinforced concrete. Erected in an area that was predominantly agricultural at the time, it is dedicated to the Blessed of Busto, who was born in the nearby Cascina dei Poveri and to the Jesuit saint Aloysius Gonzaga, protector of students.

The exterior of the church has exposed brick walls, a gabled façade and a concrete portal surmounted by a glazed triangular tympanum. On the façade are depictions of the two saints. The one of Blessed Giuliana is a mosaic by Torildo Conconi, who in 1984 reproduced a painting by Biagio Bellotti preserved in the Museum of Sacred Art of St. Michael the Archangel and dating from 1782.

The bell tower has an octagonal plan and is located next to the southeast side of the building.