Abstract: Objective: To compare the clinical and pathological features,molecular subtypes and prognosis of breast cancer between young and elderly patients.Methods: Fifty-six young patients with breast cancer,18 to 30 years old,and 120 elderly patients with breast cancer,45 to 70 years old,were divided into the young group and elderly group,respectively.The clinical and pathological features,molecular subtypes and prognosis between two groups were compared.Results: The differences of the tumor size,lymph node metastasis,histological grade,molecular subtype and tumor recurrence between two groups were statistically significant(P<0.05 to P<0.01).The triple negative breast cancer occurred most often in young group.Conclusions: The clinical symptom of breast cancer in young patient is concealment,and its prognosis is poor.The clinical and pathological features,subtypes and prognosis of breast cancer in young patients are different from that in the elderly patients,the early diagnosis and treatment of which should be paid attention to.