Résumé : A new species of Bertiera (Rubiaceae) from Equatorial Guinea and Cameroon, Bertiera rosseeliana Sonké, Esono & Nguembou, is described and illustrated here. This new species belongs to subgenus Bertierella and appears to be closely related to Bertiera naucleoides. It differs from this species, however, by the features stated in the diagnosis: glabrous leaf blade (not puberulous); calyx lobes shorter (2-3 not 7-8 mm); corolla tube longer (18-20 not 5-6 mm); fruits without pedicel. © Publications Scientifiques du Muséum national d'Histoire naturelle.