This study describes biodegradation of dyes which are used in textile industries. Dyes released into the environment from industrial waste water are considered to be a serious pollution problem because of the wide spread into environment with a variety of colors. The microorganisms used in this experiment were Pseudomonas species, which had been screened from aeration tank of waste water treatment. It was found that optimum concentrations for culture media were 14g of glucose, 6g of peptone, 160 mg of Na2HPO4, 200mg of KCl, 140mg of MgSO4,.7H2O,1.0g of KH2PO4, 400mg of NaCl, 200mg of CaCl2 and dye 10ppm per litre of distilled water. The high efficiency of dye degradation was obtained at pH 7-8 and $30-35^{circ}C$. Strains screened are excellent for removal of azo and reactive dyes, which are relatively stable and difficult to degrade. Dyes of 10ppm such as mono-azo (Lot No. 180), di-azo (Lot No. 138) and reactive red(Lot No. 2) were mostly decolorlzed within 2 days and di-azo (Lot No. 151) and reactive red(Lot No. 34, No. 00166) were decolorized within 5 days in the controlled fermenter. In the case of reactive dyes, oxygen supplies showed lower biodegradability compared to anaerobic culture.