The study presents results of a floristic and mammal survey undertaken in the Sefwi-Wiawso District within moist semi-deciduous vegetation zone of the Western Region of Ghana. The floral survey involved estimating the floral distribution, abundance and diversity using the standard indices, Shannon-Wiener, Simpson's, evenness, species richness, similarity, and β-diversity, while the mammal survey was conducted using direct opportunistic observation, live-trapping (small mammals), animal spoors/trophies, and interviews. There were 271 plant species recorded, out of which 174 species comprising 172 species and 67 families of angiosperms (Angiospermae) and two species of ferns (Pterydophyta) were scientifically-named. Forty species of mammals representing eight orders were recorded, with the dominant orders being Rodentia and Artiodactyla. The greatest faunal diversity occurred in the forest reserves, where suitable habitat niches still occur. There were 48 individuals of seven species of rodents and one individual of one insectivore species captured during live-trapping, with the commonest species being common mice (Mus spp.) and brush-furred mice (Lophuromys flavopunctatus). The greatest threat to the survival of the fauna is habitat destruction. Generally, the Sefwi-Wiawso District is very rich in forest tree species, the commonest being the Celtis-Triplochiton Associations, but bad agricultural practices, bush burning, intense logging, fuelwood harvesting and pollution have resulted in poor soil quality and land degradation in certain areas. Hunting of animals for meat, and destruction of habitats were the greatest threats to faunal diversity and abundance in the Sefwi-Wiawso District. Introduction It is generally acknowledged that the forests of Africa are gravely threatened largely through anthropogenic influences like unsustainable farming practices, fuelwood over-exploitation, unauthorised logging, bushfire setting and pollution (Holbech, 1996). The forests of the Western Region of Ghana have, to a large extent, been subjected to increasing degradation over the years due to such unfavourable anthropogenic influences (Martin, 1991; Hawthorne & Abu-Juam, 1993). This situation poses serious threats to the biodiversity of the region, and its socio-economic and ecotourism potential. Located in the Western Region of Ghana, the Sefwi-Wiawso District faces increasing deforestation due to its high population growth rate and the attendant negative anthropogenic impacts outlined above. The forests of the District are being encroached upon at alarming rates, resulting in the degradation of large sections of hitherto pristine forests. This situation requires detailed and comprehensive biodiversity inventories to ascertain the current ecological status of the District's forests, to assess the extent of the negative anthropogenic impacts, and to provide the requisite data to enable the monitoring of anthropogenic disturbances over time (Bridgewater, 1996). The specific objectives of this study were to (i) identify and define the biodiversity features of sample areas of contrasting habitats in the District, particularly the floral and faunal (mammal) characteristics, (ii) assess the impact of human activities on the forest ecosystem, and (iii) recommend appropriate guidelines for conservation and sustainable use of the natural resources of the area.