The present study aims to evaluate the floristic richness of the Lwampango relict forest located in the Kaziba chiefdom in South Kivu Province, Democratic Republic of Congo. The transect technic was used to collect data. The results reveal 90 plant species divided into 79 genera and 42 families. The most represented families are: Asteraceae (17.77%), Rubiaceae (7.77%), Acantaceae (5.49%), Fabaceae (4.39%). The analysis of the flora shows that herbaceous (53%), Phanerophytes (42.86%) and Afro-tropical species (51.11%) predominate. The studied ligneous fraction has an average dbh varying between 15.3 cm and 43.6 cm. The highest relative abundance is reported in Macaranga kilimandscharica (9.79%), this species also has the highest Importance Value Index (28.02%). The relative dominance is observed in Polycias fulva (11.09%). This study reveals a diversified flora that inspires to be extended to other forest formations and forest groups in South Kivu Province and its surroundings. The results of these studies will allow the elaboration of a better data base necessary for the management and sustainable conservation of forests and the ecosystem services they provide to the population.