Breast disease is a major health problem for women, affecting all age groups. The spectrum of breast disease is wide, ranging from benign breast diseases to malignant neoplasms. The benign breast conditions are mastalgia, duct ectasia, duct papilloma, fibroadenoma, fibroadenosis, breast abscess, periductal mastitis, granulomatous mastitis, phyllodes tumor, and Paget’s disease of the breast. Malignant breast diseases are malignant phyllodes tumor and breast cancer. Breast cancer can be in situ cancer or invasive carcinoma. Lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS) are the two in situ cancers. Invasive carcinoma includes invasive ductal and invasive lobular carcinoma, and inflammatory breast cancer. Diagnosis of breast disease mainly depends on careful history taking, comprehensive clinical examination, radiological imaging, and tissue diagnosis. Treatment varies widely as per the status of disease. This chapter emphasizes common symptoms related to breast disease, clinical examination of the breast, and triple assessment.