Background: Breast cancer is the leading cause of cancer death in women worldwide. In Ethiopia breastrncancer is becoming the first common cancer and higher maternal deaths in the country. The finding fromrnthis study will have a significant benefit in promoting prevention and early control mechanisms,rnconscious the policy makers and national programs about the need of preventive, treatment, diagnosticrnand palliative care facilities and shows the way to address it on the system.rnObjectives: The aim of this study is to assâ€™s prevalence and factors contributing to late diagnosis ofrnbreast cancer among women attending at Tikur Anbessa Specialized hospital, oncology unit, AddisrnAbaba, Ethiopia, 2017.rnMethods: Facility based quantitative cross-sectional study was employed from March 2017. Systematicrnsampling technique was used involving 215 study participants. Data was collected using structuredrnquestionnaire for interview and supported from medical records. Collected data was cleaned forrnincompleteness and inconsistencies using Epi info 3.1. Data analysis was carried out using SPSS 20rnversion. Descriptive statistics including, frequencies, proportions and measures of central tendency wasrnemployed. Bivariate and multivariate analysis using Odds ratio (OR) was utilized to evaluate associationrnbetween dependent and independent variables. P-value less than 0.05 were considered as level ofrnsignificance for associations.rnResult: In this study the prevalence of late diagnosis of breast cancer is 184(88.89%) with the remainingrn23(11.11%) study participants early stage. According to this study, around 77 (52%) of the respondentsrnmentioned lack of awareness about breast cancer symptoms as a reason for late diagnosed also 61 (41.2rn%) of them reported as breast cancer relieve by itself, and 57 (38.5 %) difficult to make decision to go tornhealth facility for help seeking as the reasons for late diagnosis related with the patient. Occupation wasrnonly variable significantly associated with late diagnosis of breast cancer among the socio-demographicrncharacteristics {AOR=0.2; 95% CI (0.001-0.80)}. Others such as Health facility, consulted before beingrnreferred to TASH and breast examination done in initial consultation was significantly associated withrnlate diagnosis of breast cancer {AOR=1.10; 95% CI (2.50-4.85)}, {AOR=3.32; 95% CI (2.97-5.86)}rnrespectively.rnConclusion and recommendation: The study revealed that almost three fourth of the women wererndiagnosed for breast cancer at late stage. Awareness of breast cancer patients about early detectionrnmethods was low. Increase knowledge of women on different types of breast cancer symptom in order tornincrease early detection.rnKey Words: late diagnosis, factor and breast cancer.