The potential application of Aspergillus niger for textile wastewater treatment was investigated. The growth kinetics of A niger previously isolated from Gorgan Bay were carried out in a shaker and split air lift bioreactor under limiting nitrogen and carbon source. It was found that a glucose concentration of 0.3% has a very strong effect on decolorization. The organic nitrogen present in the effluent was sufficient during the process. The inoculum size up to 10% increased the decolorization rate rapidly. The optimum temperature of decolorization was about 28-30 degreesC. These results suggest that 1g of A. niger mycelium cell has potential application for the clean up of textile wastewater within 20h.