Calosoma deckeni is a species of ground beetle in the subfamily of Carabinae. It was described by Gersteacker. This species is found in Tanzania, where it inhabits the south-eastern slopes of Mount Kilimanjaro.
Adults reach a length of 12-18 mm. They have a reddish yellow pronotum and black to brown to yellow elytra.
The species is named for German explorer Baron Karl Klaus von der Decken.