The purpose was to examine the effects of auricular acupressure to relieve constipation in patients with breast cancer who were undergoing chemotherapy. Participants were 52 patients with breast cancer receiving chemotherapy at E University Hospital, Seoul, Korea, randomized into two groups of equal size. For the experimental group, auricular acupressure was applied to seven auricular acupoints for 6 weeks using vaccaria seeds, whereas the control group received the usual care. Constipation-assessment scores of the experimental group were significantly lower compared with the control group (p < .001). Stool-form scores of the experimental group were significantly higher compared with the control group (p = .003). Patient Assessment of Constipation–Quality of Life scores of the experimental group were significantly lower compared with the control group (p < .001). Auricular acupressure was effective at relieving constipation in patients with breast cancer receiving chemotherapy. Auricular acupressure was also a safe and acceptable nursing intervention.