Ergene River Basin is the main fluvial habitat of Thrace Part of Marmara region and known as one of the most polluted river ecosystems of Turkey. The aim of this study was to evaluate the water quality of Ergene River Basin components (Meriç and Ergene Rivers and 10 most significant tributaries of the basin) by investigating 25 trace and toxic element concentrations (Li, Be, B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sb, Ba, Tl and Pb). Water samples were collected in rainy season (spring) of 2018 from 21 stations and element levels were investigated by using an ICP-MS. Cluster Analysis (CA) was used to classify the investigated trace and toxic elements in terms of accumulation levels in the waters of Ergene River Basin and to classify the investigated stations in terms of contamination levels. According to the results of element analysis, Ergene River has Class II and Çorlu Stream has Class III water quality in terms of nickel and chromium parameters. Almost all the investigated watershed elements have Class III and Ergene River and Çorlu Stream have Class IV water quality in terms of selenium parameter. According to the results of elemental CA, 4 statistically significant clusters were formed, which were named as "Most intense elements", "Second most intense elements", "Moderate intense elements" and "Rarest elements". According to the results of locational CA, 3 statistically significant clusters were formed, which were named as "Less contaminated regions", "Moderate contaminated regions" and "Most contaminated regions".