Purpose: The purpose of this study was to identify the effects of a home based exercise program for patients with stomach cancer who were undergoing oral chemotherapy. Methods: The home-based exercise program was developed from the study findings of Winningham (1990) and data from the Korea Athletic Promotion Association (2007). The home-based exercise program consisted of 8 weeks of individual exercise education and exercise adherence strategy. Participants were 24 patients with stomach cancer who were undergoing oral chemotherapy following surgery in 2007 or 2008 at a university hospital in Seoul. Patients were randomly assigned to either the experimental group (11) or control group (13). The effects of the homebased exercise program were measured by level of cancer related fatigue, NK cell ratio, anxiety, and quality of life. Data were analyzed using SPSS/WIN 13.0 version. Results: The degree of cancer related fatigue and anxiety in the experimental group decreased compared to the control group. The NK cell ratio and the degree of quality of life of experimental group increased while that of the control group decreased. Conclusion: This study result indicate the importance of exercise and provide empirical evidence for continuation of safe exercise for patients with cancer during their chemotherapy.