The species name is occasionally misspelled as "coeruleus" (e.g.,[1]), but the spelling caeruleus is preserved by Opinion 604 of the ICZN, issued in 1961.

[2] The adult is between 3.5 and 6.5 mm (0.14 and 0.26 in) long, has reddish-brown antennae, a scantily spotted brown head and neck shield, and shiny blue elytra.

The presence of Korynetes caeruleus indicates a heavy infestation of either woodboring insect.

Adult females mate and lay eggs near or just inside exit holes, then die.

[3] It is not to be confused with Necrobia rufipes, which is also a steely blue beetle in the family Cleridae.