Résumé : This first part of the treatment of the Labiatae occurring in theDemocratic Republic of the Congo, Rwanda and Burundi provides generalfamily-level information, such as a full description, details about theclassification, distribution, uses and most important references. This is followedby some morphological particularities, a list of all subfamilies and genera aswell as an identification key to all 35 genera occurring naturally or as escapesfrom cultivation in the Flora region. Furthermore, a treatment of the first twosubfamilies, Viticoideae and Premnoideae, comprising a single genus eachand respectively 17 and 6 species, is provided. Each user-friendly key to thespecies is followed by the species treatments which provide full morphologicaldescriptions, synonyms, data on distribution, habitat, vernacular names and uses,as well as references to additional literature and the citation of representativespecimens. Six taxa (three species and three varieties) are endemic to the Floraregion. A total of nine line drawings and 21 colour photographs assist theidentification process.