A checklist of the vascular flora of the Democratic Republic of the Congo (DRC) has been assembled, based on literature, online databases, and herbarium collections. It includes 10,260 species (38 lycophytes, 347 monilophytes, 16 gymnosperms, and 9,859 angiosperms), belonging to 246 families. The five largest families are Fabaceae (11.8% of specific richness), followed by Rubiaceae (6.7%), Asteraceae (6.6%), Poaceae (6.1%), and Orchidaceae (5.6%). Strict endemics of the DRC amount to 1,099 species, i.e., 10.7%. Families represented by > 120 species and comprising a high proportion of endemics include Commelinaceae (endemism rate: 24%), Euphorbiaceae (21%), Asteraceae (16%), and Fabaceae (16%). A total of 461 introduced species are recorded outside cultivation in the country, i.e., 4.5% of the total flora. Solanaceae, Brassicaceae, and Amaranthaceae stand out with their higher-than-average proportions of introduced species. Herbs represent the most frequent life form (54%), followed by (sub)shrubs (17%), trees (14.5%), climbers (10%), and epiphytes (4%). The IUCN conservation status was retrieved for 2,633 species (25.7%), of which two species are extinct and 448 (17%) are assigned to a threat category (CR [Critically Endangered]: 36; EN [Endangered]: 184; VU [Vulnerable]: 228). IUCN status was retrieved for 184 (17%) of the endemic species, of which 135 (73%) are considered extinct or threatened.