The White-breasted Guineafowl Agelastes meleagrides is one of 15 bird species endemic to the Upper Guinea Forests of West Africa. The Taï region in southwestern Côte d'Ivoire probably holds one of the largest remaining populations of this species. We assessed population density in two different sectors in the southern part of Taï National Park and one sector in the N'Zo Faunal Reserve, north of the National Park. The sectors differ in rainfall patterns and hence vegetation type, as well as in previous and past levels of logging and hunting. Line transect surveys were undertaken between 2000 and 2001 with an overall survey effort of 2,883 km. Abundance was highest in the sector with the driest forest type, the N'Zo Faunal Reserve (encounter rate: 0.02 detections km−1, density: 32.9 ind. km−2), where we also observed the largest group recorded for the species so far (38 individuals). The species was almost absent in the southeast of Taï National Park (encounter rate: <0.002 detections km−1), where the impact of poaching on wildlife is strongest. The study confirms that the species reaches highest densities in drier forests and only occurs in smaller numbers in the wetter south of the Taï region. Our data also suggest that past disturbance from logging does not constitute an obstacle for its persistence. The population size in Taï National Park and N'Zo Faunal Reserve should be between 42,000 and 120,000 individuals.