Aplocnemus alpestris can reach a bodylength of about. These soft-winged flower beetles have an elongated, cylindrical body. Pronotum and elytra have a slightly shinyblack color. They are coarsely punctuated, with a long grayish pubescence. The antennae show a sexual dimorphism in their structure, as in males they are deeply serrated, while they are shallowly serrated in females.