This study presents the feeding phenology of chimpanzees in the forests of the Conkouati-Douli National Park (CDNP) as part of a larger assessment of its suitability for chimpanzee reintroduction. All phenological monitoring and follow-up were conducted using the methods outlined by Diouf & Zaafouri (2003). Observation yielded five species that were found to be used by chimpanzees. Some of these species were also found to be used by chimpanzees for nesting. A strong link between rainfall and phenology was found in the area. Most fruiting was observed during periods of slower rainfall, while flowering occurred in the rainy season. This study assessed more than 300 trees, including those of the species Staudtia kamerunensis var. gabonensis, Trichoscypha acuminata, Uapaca guineensis, Vitex grandifolia and Xylopia aethiopica, all of which are regularly found in the diet of chimpanzees in the CDNP. The patterns of fruiting and availability were also compared to those at other tropical forests, particularly those that also support chimpanzees. These results, though focused on only five species of trees, can constitute a database to guide further research in the CDNP, as well as in other tropical African forests, in order to properly assess chimpanzee food security and sustainability in the wild.