This study consists of vascular plants of Orhaneli district that is located in the south of Bursa province. During the study, 2100 plant specimens were collected from 47 different stations in the research area. At the end of identification, 713 taxa (485 species, 157 subspecies, 70 varieties and 1 hybrid) belonging to 347 genera and 82 families were determined. The distribution of total taxa according to divisio, subdivisio and classis is as follows: 14 taxa in Pteridophyta division, 699 taxa in Spermatophyta division, 8 taxa in Pinophytina subdivision, 691 taxa in Magnoliophytina subdivision, 583 taxa in Magnoliopsida and 108 taxa in Liliopsida classis. The distribution of the taxa according to the phytogeographical regions and their rates are as follows; Mediterranean element 149 (20.9%), Euro-Siberian element 89 (12.5%), Irano-Turanian element 50(7 %) and multiregional or unknown originated 425 (59.6 %). The threat categories of these endemic taxa are presented. The largest families are respectively, Asteraceae (83), Fabaceae (64), Poaceae (50), Lamiaceae (45), Brassicaceae (42) and Caryophyllaceae (41). The genera containing highest number of taxa are Trifolium L. (18), Alyssum L., Galium L., Verbascum L. (12), Vicia L., Hypericum L. (11), Euphorbia L. (9).