Research in Euphrates basin in Turkey showed the following values: temperature, dissolved oxygen, pH, nitrite, nitrate, chlorine, sulfate, iron, copper, calcium, magnesium and silica in surface waters were monitored. Significant relationships among these parameters were observed at seasonal term. Some significant (p<0.05) differences were determined among the parameters (temperature, dissolved oxygen demand, nitrite, chlorine, sulfate, iron and copper) according to seasons. pH was not determined a significant (p>0.05) differences in all seasons. However, it was also significant (p<0.05) differences the results of nitrate at summer, calcium and magnesium at spring, silica at winter as other seasons. The data of chlorine, iron, and copper in Karasu River were measured high levels according to water quality standards of EPA.