The emission of greenhouse gases can be reduced either by reducing the rate at which they are emitted into the atmosphere or by increasing the rate at which gases are removed from the atmosphere through carbon sinks. In this context, the evaluation of biomass and carbon sequestration potential by the Mambala forest massif to the east of Kikwit was studied. The general objective is to estimate the contribution level of the forest massif to the regulation of the climate system through a diagnosis of the quantities of sequestered carbon. The floristic inventory was carried out on an area of ​​1 ha delimited in the Mambala forest, made up of 5 strips of 100 m x 20 m within which, the dbh ≥10cm of the trees were measured. The non-destructive method was employed and allometric equations developed by authors were used for this purpose. 439 trees with a diameter at breast height greater than or equal to 10 cm were inventoried, identified into 56 species, divided into 28 families, the most represented of which is that of Fabaceae. The carbon contained in the biomass is 616.93t/ha. The quantity of sequestered carbon and the carbon equivalent obtained were respectively 317.05 and 984.58t/ha; the basal area was 52.07m2/ha. Based on these results, we can affirm that this ecosystem is a real natural carbon sink which must be well managed, because it can contribute to the mitigation of greenhouse gases if it is well managed.