Background: According to Breast Cancer Screening Programs in 26Countries, 19.0% of females have breast cancer. The aim of our study is assessing the role of nanotechnology in breast cancer therapy. Epirubicin drug was selected as an example of the pharmaceutical nanosystem. Method: A cross sectional study was conducted among 300 women in Taif city and the data were collected using a self-administered questionnaire. The questionnaire determines the knowledge of risk factors and the disease stages (breast cancer). The patients also interviewed to determine the duration, the response and the feeling of any harmful symptoms after using of Epirubicin in the therapy. The answers were scored; frequencies and percentages were used for describing data. Chi-square test and a P value of (0.05) were used to determine the significant association between the participants' variables. Results: Most patients respondents were between 21 to above 70 years old. About 28.1% breast cancer patients discover the disease by the chance, while 46.9% by self-examination. 43.75% of breast cancer patients use Epirubicin drug. The effectiveness of therapy takes about 3 -9 months. 15.6% only have a serious common side effect and 18.7% have any side effect. Therefore the number of patients who accepted the therapy by Epirubicin was 78.6% Conclusion: Participants had poor knowledge about the disease and management. Using Epirubicin had a good attitude in managing time and compliance of the disease. The nanoparticle system presented in Epirubicin drug considers the solving of most common patient incompliance.