Background: Breast self-examination (BSE) is a simple, very low cost, non-invasive screening method used to detect breast cancer early which involves the woman herself looking at and feeling for any change in their breast as early as possible. Breast self-examination should be done for all women above the age of 20 years. Objective: To assess the knowledge and practice of breast self-examination among female undergraduate students in Addis Ababa University, College of Business and Economics, Ethiopia. Method: Institutional based crosssectional study was conducted to assess the knowledge and practice of breast self-examination among female undergraduate students in Addis Ababa University, College of Business and Economics. Departments were selected from College of Business and Economics by using lottery method. Then a simple random sampling technique was used to select a total of 407 female students from each department. Data was collected by using self-administered, structured and pre tested questionnaire from February 1-30, 2016. Quantitative method was employed to achieve the research objective. The data was entered into Epidata and analyzed by Statistical Package for Social Science (SPSS) window software. Binary logistic regression and multiple logistic regressions were done to confirm association between variables. Result A total of 407 respondents were enrolled in the study giving a respondent rate of 100%. 203(49.9%) of respondents had a good knowledge of BSE. Only 87(21.4%) of the study participants ever practiced breast self examination. The three main reasons for not doing BSE were didn’t know how to perform BSE 95(29.7%), had no breast problem 81(25.3%), and carelessness 67(20.9%). Previous place of residence, attitude of BSE and knowing someone suffer from breast cancer found to be significantly associated with knowledge of BSE. Breast self-examination practice had showed significant association with family history of breast cancer, knowledge and attitude of BSE. Conclusion This study revealed half of study subjects have good knowledge of BSE however, majority of study subjects didn’t ever practice BSE. Thus warrant to the concerned bodies for creation of awareness about breast self-examination and training students how to practice BSE. Key words knowledge, practice, Breast self-examination, female students