The Allium genus vegetables are of special interest since being potentially sources for selenium. In this study, the metabolization of selenite and selenate fortification at low and high levels in hydroponically cultivated Allium porrum (Leek) was investigated. The total Se analysis of nutritional solutions which was used in cultivation medium revealed that leeks had potential to accumulate Se above over 1000 mg/kg without any growth disturbance which was proved by comparing dry masses of control group with the ones fortified by Se species. Speciation analyses performed in edible parts which are leaves and stems showed that approximately 90% of total selenium was biotransformed into organo-selenium species in which MeSeCys and SeMet were found to be the most dominant in Se(IV) fortified leeks. However, selenate was found to be the most abundant species in edible parts of selenate fortified leeks especially at high levels. Although bioavailability rate of total selenium in selenate fortified leeks was found to be higher, lower amount of inorganic selenium and higher amount of MeSeCys were found to be bioavailable in Se(IV) fortified.