The city of Yamoussoukro has several abandoned green spaces that have been gradually nibbled away by city dwellers. The aim of the study carried out in this city was to evaluate the diversity of plant species present in these abandoned green spaces and to measure their carbon stock. To do this, a floristic inventory was carried out based on the surface survey plus the roving survey. The diameters at breast height (DBH) of individuals larger than 2.5 cm were measured. The biomass and carbon stock of the trees were assessed using a set of allometric equations from the literature. In total, 4687 individuals were counted, of which 1473 individuals have a DBH ≥ 2.5 cm. The number of species present in these areas is 328. The presence of species with conservation status and the relatively high carbon stock (302.11 t/h) show their importance in the urban environment.