The oxidation of polyethylene surfaces with a range of mild oxidizing agents enhanced by the use of ultrasound is described. The use of sonochemical methods allows significant levels of surface modification to be achieved using oxidizing agents such as hydrogen peroxide and persulfate salts around ambient temperatures under mild conditions. Changes in the water contact angle and attenuated total reflection IR spectroscopy were used to follow the changes in surface chemistry. Variation of the experimental conditions such as treatment time and sound intensity allowed control over the extent and nature of the surface oxidation. Although the changes achieved with laboratory equipment are relatively slow, more significant effects could be obtained at higher ultrasound intensities.