The Dardanelles (Canakkale Strait) is a water passage connecting the Aegean Sea and Sea of Marmara. The average depth of the Dardanelles is 60 m; the deepest part reaches more than 100 m. Environmental parameters such as temperature, pH, salinity, dissolved oxygen and total dissolved solids were measured at different depths in the Dardanelles. The sampling period was between December 2002 and March 2003. All the data was measured by a YSI 6600 Model Multiple Probe System. Also, a Geographic Information System was used to create a tabular and spatial database, with the aim of integrating the physicochemical properties in the Dardanelles. Temperature and salinity profiles by the Geographic Information System showed that there was stratification and formation of two different water masses in the Dardanelles. The measurements showed that lower layer waters (>20 m) are saltier than upper layer waters of the Dardanelles. Therefore, the lower layer waters also hold higher values for total dissolved solids. Although the temperature and salinity characteristics of the Dardanelles are specific due to its topographic structure and some fresh water discharges, the stratification in the Dardanelles is generally similar to other parts of the Turkish Strait System (Bosphorus and Sea of Marmara) because of large salinity differences between the Aegean and Black Sea.