BACKGROUND: Women with breast cancer experience various challenges. Prescription of health information provides appropriate information at appropriate time to the appropriate person and plays a role in empowering self-care and improving health. The current research aims to evaluate the effect of health information prescription on self-care power of women with breast cancer. MATERIALS AND METHODS: This semi-experimental quantitative study was done using pretest and posttest method in one group of 61 women with breast cancer selected from the Women's Cancer Center of Khatamolanbia Hospital using purposive sampling method. Data were collected by an author-made self-care questionnaire and patients' self-care score was calculated at the first visit (before health information prescription) and the second visit (after health information prescription). Data were analyzed using the SPSS version 23 software and analysis of variance at a statistical significance level of P < 0.05. RESULTS: Total mean score of self-care in women with breast cancer was 40.97 and 115.3 before and after health information prescription, respectively. Increase of mean was observed in all subscales of self-care score from pretest to posttest so that change in posttest was higher in subscales of effective implementation of treatment and prevention from disabilities and personal functioning regulation (39.44), specialized knowledge on breast cancer (30.46), searching medical services and cooperation with treatment group (28.59), and awareness and attention to impacts and results of breast cancer (16.81). CONCLUSION: Health information prescription improves self-care power of women with breast cancer, and it is necessary to provide health information services in order to support women's self-care by the health authorities.