The aim of this study is to specify the urban ecologic characteristics of Istanbul and to show their reflection to the vascular wall flora of the Anatolian side, which is a distinctive wall habitat. Plants samples of the urban habitat were collected from the top and vertical surfaces of walls during 2005-2007. A total of 101 taxa (81 species, 13 subspecies and 7 varieties) belonging to 74 genera and 33 families were recorded. It was determined that 80 species were Dicotyledones while 1 was Monocotyledone. The families with the largest number of taxa were Asteraceae (18 species, 22.22%), Poaceae (8 species, 9.87%), Lamiaceae and Brassicaceae (5 species, 6.17%), and Polygonaceae and Scrophulariaceae (4 species, 4.93%). The most common plant species on walls were Parietaria judaica L. (Urticaceae), Stellaria media (L.) Vill. subsp. media (Caryophyllaceae), and Mercurialis annua L. (Euphorbiaceae). The percentage of phytogeographical elements among the recorded taxa varied as follows: Euro-Siberian (6 taxa, 7.41%), Mediterranean (11 taxa, 13.58%), E. Mediterranian (2 taxa, 2.47%), Irano-Turanian (1 taxon, 1.23%) and unknown (61 taxa, 75.31%). It was found that 6 taxa (7.41%) were cosmopolitan, 12 (14.82%) were widespread while 1 (1.23%) was endemic. The results were compared with some other European wall floras and some similarities and dissimilarities were noted.