Purpose: To develop a expressive writing program for women with breast cancer and to identify its effects on stress physical symptom, cancer symptom, anxiety, depression, and QOL. Methods: A non-equivalent control pre-post design was used. Participants were recruited from self-help groups in six hospitals and were assigned to the experimental group (29) or control group (29). Data were collected before, after, and at four weeks after the intervention program. Changes in the variables were evaluated to test effects of the developed program, using X 2 -test, Fisher's exact test, repeated measures ANOVA, and paired t-test. Results: The expressive writing program was developed for women with breast cancer based on Pennebaker's expressive writing. Significant differences were found between the two groups for stress related to physical symptoms (p< .00) and quality of life (p= .024). No significant differences were found in cancer symptoms, anxiety, or depression between the two groups. Conclusion: The results indicate that the expressive writing program designed to express cancer-related deep thoughts and emotions helps in decreasing physical symptoms and improving QOL. Further studies are needed to identify the effect on emotions such as anxiety and depression for women with breast cancer with above average levels of anxiety and depression.