The jewel of the Oberlahnstein parish church of St. Martin is the organ.

The most valuable musical instrument was built by the famous organ builder Johann Michael Stumm in the Hunsrück from 1742 to 1744. The organ builders needed 40 days for the installation of the organ on site.

The organ is a work with 22 registers, two manuals, and a pedal. It was restored in the 1960s. The architectural development of the church on the central high road is reflected in four architectural styles: In 1190, a three-nave Romanesque basilica was built, whose choir was extended in Gothic style in 1332. In the mid-18th century, the Baroque central nave was constructed, and at the end of the 19th century, the side naves were added.