The reformed church of Bierum was badly damaged in World War Two, and owes its suspiciously mint condition to an extensive restoration in 1945-1950.
The oldest part of the church is the tower, which was built in the first quarter of the 13th century. This tower is the only intact example of a reduced westwork in the province of Groningen, having a chapel inside and being incorporated in the westernmost trave of the nave. More unusual is the huge buttress that prevents the tower from sagging. This buttress, which has a pointed arch, probably dates from the 15th century.
The nave dates from the second quarter of the 13th century and features details in both Romanesque and moderate Romano-gothic style; the windows however are reconstructions dating from the restoration and replacing larger Gothic ones. Inside the church has typically Romano-gothic mellon-vaults. The choir dates from the first half of the 14th century and replaced a semi-circular one.