The Catholic parish church of Kelmis is dedicated to the Assumption of Mary into Heaven. This church, built in the neo-Gothic style, was officially opened in 1865. Since then, the red brick building has hardly changed at all on the outside. The erection of the Church of the Assumption was made possible by financial aid from the Vieille-Montagne mining company and the Belgian and Prussian governments.
The choir stalls in the church date from the year 1869. The former main altar, the central panel of which today serves as a tabernacle, was erected in 1867. The bells date from 1870. The way of the cross was set out in 1879.
On the right-hand side of the church, in the porch of the main portal, there is a memorial plaque which is probably unique in the way it was designed: it lists the sons of the village who were killed on both fronts in the First World War (1914-1918).
