Factor V Leiden (1691 G-A) (FVL) causes activated protein C resistance and is the most common thrombophilic mutation worldwide. Guanine to adenine change leads to a replacement of glutamine to arginine at amino acid position 506. It is most prevalent among Caucasians but not found in Japanese and Africans [1,2]. Anatolia is at the crossroads of different civilizations and lies central to three continents. Thus, it is logical that different frequencies could be expected in different parts of the country. However, as FVL is presumed to have originated from the Middle East some 15,000-30,000 years ago, high frequency among the Turkish population can be expected .