Background: Breast Self-Examination is a process that women examine their breasts to detect any abnormal swelling or lumps in order to seek prompt medical attention. Even though breast self-examination is shown to be the least expensive, less time consuming and non-invasive screening method, still there is a gap in practice. Furthermore, the information among more risky population which attends anti retro viral therapy is too limited. Objective: To assess breast self-examination practice and its associated factor among women who attended Anti-Retro Viral Therapy clinic in Bahir Dar city administration, Northwest Ethiopia. Methods: An institution based cross-sectional study was conducted among 660 women who attended Anti-retro viral therapy clinics from March 1 to March 30 2020. Systematic random sampling technique was used to select study participants. Pre-tested interviewer-administered questionnaires were used to collect data. Data were entered in to EPI data 3.1 and exported to SPSS version 23.00 software for analysis. Binary logistic regression model was fitted to identify factors associated with self-breast examination. Variables with a p-value less than 0.2 in bivariable regression were candidates for multivariable regression. Adjusted odds ratio with a 95% confidence interval and p-value less than 0.05 was used to determine the association between independent and dependent variables. Hosmer and Lemeshow test was used to determine model fitness. Result: Among 641 study participants, 224 (34.9%) have ever practiced breast self- examination. Women who attended college or above [AOR=4.04, 95% CI (1.65,9.90)], rich [AOR=6.64, 95% CI (2.72,16.20)], knowledgeable about sign and symptom of breast cancer [AOR=5.13, 95%CI( 2.55,10.31)], risk factor of breast cancer [AOR=3.62, 95% CI (1.85,7.07)], positive Attitude towards breast self-examination [AOR=2.76,95% CI (1.41,11.84)], family history of breast cancer [AOR=3.68,95%CI (1.14,11.84)], knowledgeable about breast self-examination technique [AOR=2.64, 95% CI (1.23,5.66)] had higher odds of breast self-examination practice. Conclusion: The practice of breast self-examination is low. Participants’ level of knowledge on breast cancer, breast self-examination techniques were factors significantly associated with breast self-examination practice. During their regular visit for other issues, education and information dissemination about the benefit and techniques of how self-breast examination be practiced was recommended. Key words; Breast self-examination, breast cancer, knowledge and sign symptom