Breast disease is a common surgical problem. It constitutes symptomatic disease, including breast lumps, nipple discharge, and breast abscesses, as well as asymptomatic disease detected on the NHS Breast Screening Programme (BSP) and patients identified at high risk of familial cancers. It is a busy subspecialty. Referrals for symptomatic breast disease primarily arise from primary care, where they constitute approximately 3% of general practice consultations. In addition, the NHS BSP screened over 2,000,000 women in 2014, of which 4.3% were referred for assessment. The cases in this chapter cover presentations that will be commonly encountered within the breast surgery unit, including the assessment of a breast lump and the surgical management of underlying benign and malignant pathology. It also covers the assessment and management of nipple discharge, as well as lactational and non-lactational breast abscess.