The reformed church of Heumen, its former name is St. Gregorius, is a one-aisled building. The nave dates from the 12th century but was heightened and covered by a new layer of bricks in the 14th century. The old windows were closed and new, larger ones were made. In the 19th century the nave was plastered. Also in the 14th century, the lower part of the tower was built, which is opened towards the nave. In the 15th century the upper part was added. The late-Gothic choir dates from the 15th century. Traces indicate that it had a sacristy.
Unlike the big catholic church of Heumen, the reformed church survived World War Two without major damage.