This paper aims to assess the surface water quality of the Seybouse River using a model of the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI). The study area is located in the basin of the lower Seybouse River, north-east Algeria. The method involved the calculation of the WQI, based on the measurement of bacteriological and physico-chemical parameters. Water samples were collected from 13 sampling stations; observing the river and its most important tributary. The analysis of these samples showed that the water index of the river ranked as poor. The degradation of water quality of the river is mainly due to the lack of control over discharged materials and lack of water treatment.