Abstract Textile dyeing process is an important source of contamination responsable for the continous pollution of the environment. Control of water pollution has importance for both organisms, which live in water and those who benefit from water. Many dyes reaching the water source are difficult to decompose and cause many problems due to their carcinogenicity. Consequently, it is important to remove these pollutants from wastewater before their final disposal. This paper reports the resuls of the biosorption of Terasil dye on dead Aspergillus niger biomass. The adsorption behavior of the dye as a function of temperature, pH and initial dye concentration were also studied. Adsorption data were fitted to Freundlich, Langmuir and Sips isotherms and their corresponding adsorption parameters such as KF, n and KL respectively was calculated.