Doxorubicin (INN, pronounced /ˌdɒksəˈruːbəsɪn/; trade name Adriamycin; also known as hydroxydaunorubicin) is a drug used in cancer chemotherapy. It is an anthracycline antibiotic, closely related to the natural product daunomycin, and like all anthracyclines it intercalates DNA. It is commonly used in the treatment of a wide range of cancers, including hematological malignancies, many types of carcinoma, and soft tissue sarcomas.

The drug is administered in the form of hydrochloride salt intravenously. It may be sold under the brand names Adriamycin PFS, Adriamycin RDF, or Rubex. It is photosensitive and it is often covered by an aluminum bag to prevent light from affecting it.