The Basiliek van Onze-Lieve-Vrouw van het Heilig Hart (Basilica of Our Lady of the Sacred Heart) is built in neogothic style, which is quite rare in the Dutch province of Limburg. Its architect was J. Kayser, a pupil of the well known Dutch architect P.J.H. Cuypers. The first stone was laid on 2 June 1875, a marble stone which came from the catacombs of the Holy Callixtus and was sent by Pope Pius IX. The building was completed in 1877 and consecrated on 5 July 1879 by the bishop of Roermond.

The basilica was the first Dutch church - in 1883 - to be bestowed the ecclesiastical distinction of basilica. Following on from the 'great' basilicas in Rome and Assisi, by the end of the 19th century the Church was also extending the title of basilica minor (small basilica) to churches of distinctive importance and aesthetic value. The charter granting the title of basilica was signed by Pope Leo XIII on 6 May 1883.

The interior of the basilica is particularly richly decorated. The high vaults of the nave and the presence of the two galleries muffle the light, so that the church is rather dark, almost mysterious. The choir and the altar are lit by the windows of the tower. The most special feature of the basilica in Sittard are the more than 1.400 votive stones that have been donated. Texts on these stones ask Our Lady of the Sacred Heart for favours. These stones give the church a very colourful and eye-catching character.