In the perspective of using cocoa as a response to climate change, a preliminary carbon stock assessment was conducted in cocoa agroforests of the Bengamisa-Yangambi forest landscape in the north-east of Democratic Republic of Congo (DRC). Data were collected in 25 plots of 2500 m2 each, spread over 16 villages. Above-ground carbon stock assessment on cocoa trees and their associated plants revealed that cocoa agroforests store on average 44.48 Mg ha−1 of above-ground carbon of which, cocoa-associated plants represent 83.68%. The diversity (species richness) of cocoa associated plants determine the level of above-ground carbon stored in cocoa agroforests. Trees less than 50 cm in diameter stored a larger amount of above-ground carbon. Cocoa agroforests with associated plants dominated by forest species (Model F) store 1.76 and 1.72 times more carbon, respectively, than those where associated plants are dominated by oil palm (Model P) and a mixture of plant types (forest species mixed with oil palm plants, or Model FP). Associated plants inside cocoa agroforests also play additional roles to support livelihoods such as health care, household consumption and timber. Therefore, beyond carbon storage, cocoa agroforest is an important reservoir of some local species and thus useful for biodiversity conservation and local livelihoods. As cocoa agroforests in DRC are recognized as one of the main responses to climate change, this study constitutes an early contribution to the process of reducing emissions from deforestation and forest degradation (REDD +) in forest landscapes in this country of the Congo Basin.