Knowledge of the diversity of the species, their distribution and that of the pressure factors weighing on the fauna of a protected area are essential to better appreciate the conservation status and guiding decision-making for management. This study aims to contribute improving knowledge of the fauna of Taï national Park (TNP) by providing the first information about the diversity of medium and large-sized mammals and the threats to them in the PK28 and Apollinaire quasi-islands (hereafter island). Data were collected using 23 camera traps and during recce surveys at those islands in the north of the TNP, between January and February 2019. In total, 13 species of mammals were identified. Medium and large-sized mammals were more diverse at the PK28 island than at the Apollinaire island. Two of the species identified on those islands are classified as threatened species according to the Red List of the International Union for the Conservation of Nature. It was an endangered species (EN), the common pangolin (Phataginus tricuspis) and a vulnerable species (VU), the Leopard (Panthera pardus). Furthermore, anthropogenic threats were observed with 59.68% of the indices of human aggression on the island Apollinaire against 40.32% of these indices on the island Pk28. This very valuable study underlines the need to increase conservation efforts on the islands by integrating them into the ecological monitoring and the surveillance programs, in order to better understand the ecology of the animals that exist there and to reduce illegal activities that threaten them.