In this study, the effectiveness of ozone as an alternative bleaching agent to hydrogen peroxide was investigated for cotton bleaching. The conventional method for cotton bleaching uses hydrogen peroxide, therefore; hydrogen peroxide bleaching was applied for preparing control samples. Ozone treatment were applied on the fabric for 2 different temperatures (30 degrees C-80 degrees C) and one treatment time (30 minute). The whiteness/yellowness, desizing, tensile strength, weight loss (%), COD (Chemical Oxygen Demand) values were tested and reported. Considering the whiteness/yellowness and desizing values of 30 degrees C-30' and 80 degrees C-30', the 30 degrees C-30' values were better than 80 degrees C-30' values. The reason is probably the less solubility of ozone gas at elevated temperatures. Conventional peroxide bleaching yielded higher whiteness values at the studied circumstances however the COD values were much less for ozone treatment. These values of the hydrogen peroxide were less suitable for the ecological approach compared to ozone treatment.