Saint Louis Cathedral is one of the main, and until the beginning of 2006 the largest Catholic church in Bulgaria. The patron saint of the church is Louis IX.

The church was built in the 1950s during the time of the Apostolic Vicar Andrea Canova. Here in 1861 the first organ in Bulgaria was installed, which was later replaced by a larger one.

In 1931 a wildfire severely damaged the temple and destroyed the organ. After the fire in which the carved ceiling of the middle nave of the cathedral burned, the whole church Saint Louis was rebuilt. It was painted by the artist Krastyo Stamatov. The current neoclassical facade is the work of architect Kamen Petkov. On May 8, 1932, Saint Louis Cathedral was rededicated.

The bell tower was built in 1898 and is equipped with 5 bells made in Bochum, Germany. The bells are a gift from Pope Leo XIII. In 1991 a new pipe body with 12 registers was installed. In the right part of the cathedral is the tombstone of the Bulgarian princess Marie Louise - Ferdinand's first wife, mother of Boris III and grandmother of Simeon II Saxe-Coburg-Gotha. Princess Marie Louise was deeply connected with Plovdiv and often stayed in the city on charitable missions. The princess, born in Italy, was extremely religious and maintained a strong spiritual connection with the Roman Catholic Church, her godfather was Pope Pius IX himself and during her visits to the city she was a frequent guest of the Bishop of Plovdiv.