Route 108 is a short highway in the Missouri Bootheel. Its northern terminus is at U.S. Route 412 about two miles (3 km) north of Arbyrd, the only town on the route; its southern terminus is the Arkansas state line about six miles (10 km) south of Arbyrd. It continues into Arkansas as Highway 77. This is one of the few even numbered highways in Missouri that is designated as a north–south route.

Route 108 begins at the Arkansas state line in Arkmo, Dunklin County, where the road continues south into that state as Highway 77. From the state line, the route heads north as a two-lane undivided road, passing a few homes and businesses in Arkmo before running through farmland. The road continues through rural areas to the southern edge of Arbyrd, where it reaches an intersection with Route 164. At this point, Route 108 turns east to form a concurrency with Route 164, with the two routes passing through more fields before running to the south of industry. Route 108 splits from Route 164 by heading north on East Frisco Street, passing homes and a few businesses. Route 108 leaves Arbyrd and heads through more agricultural areas before reaching its northern terminus at US 412.

The entire route is in Dunklin County.