In this study quality assessment of sediments in effluent-dependent/dominated streams of the Ergene river based on chemical and ecotoxicological investigations is presented. In chemical analyses heavy metals were analysed. Acute toxicity tests were applied by bacterial luminescence method with Vibrio fischeri and expressed as toxicity unit (TU) defined as 100/EC50. This study shows that there is a lack of wise management of effluent-dependent/dominated water bodies in the basin and in order to prevent pollution caused especially toxic pollutants arise from sediments in such rapidly industrialised areas, toxicity assessment should be obligatory to effluent discharges. The results also indicated that sediments of these water bodies have potential adverse effects to aquatic systems. Because there were no significant correlations between chemistry and toxicity of sediments in the study determination of pollutant groups which caused toxicity should be determined for reduction of toxicity and adverse effects to aquatic environment.