This study was carried out at Bibita Forest (Gura Ferda), southwest Ethiopia to determine floristic composition, vegetation structure and to identify community types and to investigate the role of environmental factors in the distribution of the vegetation. 60 relevés, 20 m x 20 m at 25 m altitudinal drop along an altitudinal gradient were laid to collect the data on cover–abundance (for trees and shrubs), DBH, height, density, seedling and sapling count (for trees only). The data on herbaceous species were collected from five, 5 m x 5 m subplots laid at four corners each and one at the centre of the large relevé. Two soil samples were taken from each relevé at a depth of 0–10 cm (topsoil) and 30–50 cm (subsoil). The analysis for soil pH, % sand, % clay, % silt, and Electrical Conductivity (EC) were done. A total of 196 plant specimens belonging to 74 families and 170 genera were identified. The five most dominant families were Rubiaceae and Asteraceae (13 species each), Euphorbiaceae and Acanthaceae (9 species each) and Fabaceae (8 species). Out of 196 species 13 were endemic to Ethiopia. Ipomoea involucrata Beauv. and ? Harungana madagascariensis Lam. ex Poir. belonging to the families Convolvulaceae and Clusiaceae respectively were found to be new records for Ethiopia. Six community types were identified at 0.65 to 0.75 dissimilarity levels and each community was named after dominant tree and/or shrub species. The study on vertical stratification showed that Bibita Forest(Gura Ferda) has the upper storey (above 29 m), middle storey (15–29 m) and lower storey (below 15 m). The study on vegetation and population structure showed that the density of tree species was high at the lower class levels. Density of trees greater than 2 cm DBH (ca. 777/ha), for height greater than 6 m the tree density (ca. 673/ha), basal area (ca. 70/ha), frequency of all the tree species (716/ha) and the respective IVI values for each tree species were also calculated. The comparison of Bibita Forest (Gura Ferda) with other forests in Ethiopia with respect to tree densities, percentage distribution of tree species, basal area and phytogeographical comparison was done. Soil environmental factors such as pH of the top and subsoils, clay and sand particles of both the top and subsoils showed significant relations with altitude, species richness and diversity.