The transition after hospitalization is a vulnerable period when adverse events like unplanned readmissions may occur. Unplanned readmissions with patients undergoing chemotherapy that are the result of gaps in communicating the discharge plan may be preventable. Several transitional care interventions have been explored, and one of these is the nurse discharge phone call. This project explored the effect of a nurse-led transitional discharge phone call within 30-days after hospital discharge on unplanned readmission due to chemotherapy among patients in the medical-oncology compared to patients without a nurse-led transitional discharge phone call. A nurse-led transitional discharge phone call was implemented within 48 to 72 hours after discharge from the medical-oncology unit of a hospital in the northeastern region of United States to determine its effectiveness in reducing the number of unplanned readmissions due to chemotherapy. The Donabedian model, the Iowa model of evidence-based practice to promote quality care, the diffusion of innovation theory, and the health belief model served as the theoretical underpinnings of the project. Seven patients undergoing chemotherapy received the discharge phone call, and none were readmitted due to cancer-related complications. The unplanned hospital readmission rate was 0% compared to the 14.17% in 2017. The findings of this project might contribute to positive social change by helping the community of patients on chemotherapy to have a better transition process through acquiring necessary information for their postdischarge care and thus mitigating the possible causes of unplanned hospital readmission.