Purpose: The purpose of this study was to identify the changes in body weight, anxiety, depression, and quality of life in patients during a one month period following a radical gastrectomy. Methods: Data were collected from 30 patients with gastric cancer from July 2, 2012 through December 31, 2012, at C University Hospital, Gwangju, South Korea. The body weight, anxiety, depression, and quality of life (QoL) of the patients were measured using structured questionnaires the day before surgery, day 7 postoperative, and 1 month postoperative. Results: There were significant changes in the average body weight and the general health status/QoL, the functionality, and the symptoms of general QoL, and the functionality and the symptoms of specific QoL during the postoperative 1 month period (${chi}^2=52.47-7.68$, p<.001-.022). Conclusion: Oncology nurses should assess the nutritive conditions of gastrectomy patients carefully to avoid malnutrition during the postoperative 1 month period. Also, as the general and specific quality of life changes during the postoperative 1 month period, adequate support and sufficient attention should be provided to these patients to minimize the negative influence on quality of life, and to assist them in recovery to the preoperative state.