Breast cancer (BC) is one of the most heterogeneous types of cancer and is characterized by several molecular subtypes. Descriptive cross-sectional study was conducted on 137 confirmed BC cases at Tikur Anbessa Specialized Hospital (TASH) in Ethiopia from December 2015 to November 2016 to assess the biological and clinicopathological characteristics of BC in Ethiopian women patients. Socio-demographic characteristics of the study subjects was obtained with pretested structured interview and clinical data was collected from the Hospital records. Surgical specimens were analysed histopathologically with hematoxyline and eosin staining, and Immunohistochemistry analysis was conducted with specific antibodies to ER, PR and HER2. The mean and median age of the study participants were 47 and 46.7, respectively. More than 50% of the patients were categorized in the age group of 15-40. Sixty percent were in the age group of 41-100. Infiltrating ductal carcinoma was the most common type of BC (70%) in this study, followed by lobular carcinoma (8.5%). Almost all of the BC cases under study were at advanced stage of the disease: 48.5% were with stage III and 51% were grade II tumors. Half of the study participants belonged to T2 tumor size (2-5 cm) and 52.3% of the patients had axillary lymph node metastases. Sixty five percent were ER+, 58% were PR+ and 28% were HER2+. Luminal A was the most common tumor subtype (54%), followed by luminal B (22%) and TNBC (18%). Based on crude analysis, patients with family history of BC had a lesser likelihood of being ER+ as compared to those patients with no family history of BC [COR=0.10 (95% CI: 0.028, 0.34)]. None of the other risk factors were correlated with the prevalence of ER+ results. In conclusion, the age distribution of BC cases in this study suggests the need to create awareness and improvement of advanced diagnostic services and make available screening programs for younger people. In a resource poor setting like Ethiopia, the use of anti-estrogens (like tamoxifen) in treatment of BC cases with undetermined receptor status could be helpful as most BC cases are ER+ and hormonal therapy is relatively easily available.