The use of antibody-drug conjugates is expected to transform the management of human malignancy. Antibody-drug conjugates for cancer treatment are designed to deliver anticancer drugs to tumor cells. The main components of such conjugates are a monoclonal antibody that binds to a tumor antigen, an anticancer drug to inhibit tumor cell growth and a linker that serves to conjugate the antibody and drug. The antibody-drug conjugates developed and approved for breast cancer treatment are ado-trastuzumab emtansine, (fam)-trastuzumab deruxtecan-nxki and sacituzumab govitecan. The mechanisms of action, clinical uses and toxic effects of these antibody-drug conjugates are discussed.