At the base of the abbey of Sint-Truiden was a monastery, a community of monks, founded around 655 by Saint Trudo in the town of Sarchinium (Zerkingen; referred to as Sint-Truiden since the 12th century). After Trudo's death and his canonization, the monastery became a place of pilgrimage. Some early inhabitants of the monastery were also canonized (Eucherius van Orléans and Libertus van Sint-Truiden). In the 9th century, probably shortly after 817, the Rule of St. Benedict (Regula Benedicti) was adopted. In 883 the abbey was destroyed by the Normans.
The first monastery probably consisted of a stone church and wooden monastic buildings. Around 950, Bishop Adalbero I of Metz, who was also abbot of Sint-Truiden, had a new three-aisled church built, a large building measuring 50 m long and 24 m wide for that time. Until the 13th century there was constant interference from the Diocese of Metz; this had gained importance in the region because Trudo had donated Zerkingen (and probably also Webbekom and Zelem) as compensation for his studies with Bishop Chlodulf of Metz.
In 1975 a catastrophic fire took place in which part of the baroque abbey buildings were destroyed and the seminary church from 1845 was also lost. In 1992, an explosion took place at the complex, destroying the abbey mill. In 1999, the contours of the Romanesque abbey church on the abbey grounds (the so-called Kerkveld) were made visible by means of gabions. Eight steel columns also mark the position and height (18 m) of the pillars in the southern nave. The tower and the crypt were made accessible around the same time by means of an electronic entrance system, whereby after payment one receives a code with which a gate can be opened on the spot. The Kerkveld itself is free to enter. A bronze model of the abbey church in its heyday is placed at the foot of the tower.