The known species of the longicornis species-group in the genus Chaetocnema Stephens, 1831, are revised. A diagnosis of the C. longicornis species-group is given and five new species are described from Republic of South Africa and Democratic Republic of Congo: C. kapirensis sp. n. (Lualaba Province), C. mariobiondii sp. n. (Kwa-Zulu Natal, Weza), C. zulu (Kwa-Zulu Natal, Central Drakensberg), C. mapumalangaensis (Mapuma langa), and C. phuthaditjhabensis (Free State). Redescription and line drawings of male and female genitalia of C. longicornis Jacoby, 1895 and C. reprehensa Bechyné, 1960, and SEM photographs of particular morphological aspects of all species are also included. Finally ecological data on some species are supplied.