Sankt Mortens Kirke is the smaller of Næstved's two medieval churches, a short walk from Sankt Peders Kirke in the town centre. It dates from the 13th century and has a simpler, less embellished interior than its larger neighbour — though it retains medieval brick vaulting and some original features.
The church is still in regular use as a parish church. It is worth a quick visit if you are already exploring the old town, if only to see how the two medieval churches contrast. Together they speak to the importance that Næstved held as a regional centre in medieval Denmark.