The results of measurements of the rate of arrival of defects at dislocations in copper doped with varying amounts of oxygen are presented. The defects were created continuously during the measurement by gamma‐irradiation, and the arrival of defects at the dislocations was detected by measuring the dislocation damping. The rate of arrival of the stage III defect at the dislocations was not affected by the oxygen content of the copper. This result indicates that the binding energy between oxygen and the stage III defect is considerably less than the motion energy of the defect. Some evidence for a significant binding between oxygen and another defect (presumably the vacancy) created by the irradiation is presented.