A total of 819 species of the vascular plants belonging to 84 families and 370 genera were recorded in the Tahtali Mountains (provinces Adana and Kayseri), Turkey. Now, Kavşak and Köprü dams are being built in this area. The phytogeographic elements were represented in the study as follows; Mediterranean 178 (21.7%), Irano-Turanian 128 (15.6%), and Euro-Siberian 46 (5.6%). The phytogeographic region of taxa 467 (57.0%) was unknown or multiregional. The number of endemic species was 152 (18.5%). The spectrum of the basic life forms were as follows; Hemicryptophytes 40.2%, Therophytes 25.1 %, Chamaephytes 13.3%, Phanerophytes 10.5%, Geophytes 9.3%, Hydrophytes 1.0%, and vascular parasites 0.6%. According to the IUCN Red List Categories, 157 threatened plant species were found in the study area.