Background: Breast cancer in the young refers to a diagnosis of breast cancer in a female under the age of forty years. This is considered a distinct disease with different risk factors, biology, and prognosis. Young age at breast cancer diagnosis is reportedly more common among African-Americans. The highest proportion of breast cancer in the young has been reported in Africa. Early detection of breast cancer in Africa is hampered by lack of access to health care services, appropriate screening tools, and high cost of magnetic resonance imaging for the high risk groups. Despite a worse prognosis, management of breast cancer in the young has remained similar to that in the old females. Regional differences in the characteristics and outcomes of breast cancer in the young have been reported. There are no studies published on breast cancer in the young from the East African region. This study describes and compares the risk factors, clinicopathologic characteristics and outcomes of breast cancer in young females (<40 years>old) compared to the older females (>/= 40 years) at the Aga Khan University hospital, Nairobi (AKUH-N). Methods: We did a retrospective survey of all patients diagnosed with breast cancer at AKUH-N oncology unit between March 2012 and March 2015. We extracted data on age at diagnosis, clinical presentations, risk factors, tumour pathologic characteristics, and outcome. Results: A total of 228 breast cancer cases were diagnosed between March 2012 and March 2015, of whom 30% (69/228) were categorized as young while 70 % (159/228) were equal to or older than 40 years of age. The mean ages were 32 years, 52 years and 47 years for the young, old, and entire population of breast cancer cases respectively. All the young presented with a breast lump while 81.8% of the old had complained of a lump (P=0.001) at presentation. Compared to the old young females (54% vs. 46%, OR=2.489, P=0.045) presented earlier, and 5.5% had atypical hyperplasia (P=0.021). The young females with breast cancer had a lower weight (71kg vs. 75Kgs respectively, P=0.021). Though not statistically significant, the young females had more metastatic disease at presentation compared to the old (17.5% vs. 8.5% P=0.148). Compared to the old women, the young were more likely not to undergo surgery (21.9% vs. 5.8%, P=0.001), less likely to undergo modified radical mastectomy (31.2% vs. 54.2%, P=0.001) and preferred breast conserving (45.3% vs. 38.9%, p=0.001). Similarly, the tumours in the young