Textile wastewater is known to be highly resistant to biodegradation under both natural and wastewater treatment plant conditions. However, ozonation and UV-radiation can be used to increase the biodegradability of the biologically resistant compounds. In our studies two different real textile wastewater samples were taken from a knitting company located in Lodz, Poland. Dyeing wastes were treated by the following methods: ozonation, hydrogen peroxide treatment and simultaneous oxidation by ozone and hydrogen peroxide. The effluents before and after the treatment were analysed according to the requirements of applicable Polish Standards, which included pH, colour threshold, COD and BOD, anionic surfactants, and soluble substances. The aim of these experiments was to compare the yield of impurity destruction in the effluents treated. Generally the best results were obtained by the simultaneous use of ozonation and hydrogen peroxide. The results obtained suggest that simultaneous ozonation and use of hydrogen peroxide can be applied successfully on a technological scale.