Two days after Schuwe Maandag, this school in Roeselare was repurposed as a military hospital with an operating theater. There were several departments, including dentistry, infectious diseases, an area for disinfecting medical equipment and a morgue. The Seminarie had a capacity of around 1000 patients, who were brought in by tram. The Seminarie was one of the most important German hospitals behind the war front. It counted around 150 staff members, including the famous spy Martha Knockaert, who worked as a nurse. 

During the war, education at the Seminarie was at a low ebb, as most teachers had been conscripted into the army. Towards the end of 1914, teaching activities in the building had ceased altogether. Classes were taught in private homes in the Noordstraat and in parish halls, shops and cafes. In January 1915, students had but a few hours of class every day and were asked to spend the remainder of the day doing homework at home. Before the war, many children from Izegem were able to attend the Seminarie because they could spend the night there. As this was no longer possible during the war, those pupils were forced to walk the long way to the school every day.

During the bombing of Roeselare on 21 July 1917, the Seminarie was demolished.