.png | CAS_number = 50-76-0 | ATC_prefix = L01 | ATC_suffix = DA01 | ATC_supplemental = | PubChem = 2019 | DrugBank = APRD00124 | chemical_formula = C₆₂H₈₆N₁₂O₁₆ | molecular_weight = 1255.42 g/mol | bioavailability = | protein_bound = 5% | metabolism = | elimination_half-life = 36 hours | pregnancy_category = | legal_status = | routes_of_administration = }} Actinomycin is any of a class of polypeptide antibiotics isolated from soil bacteria of the genus Streptomyces.

It was the first antibiotic shown to have anti-cancer activity, but is not normally used as such, as it is highly toxic, causing damage to genetic material. It is mainly used as an investigative tool in cell biology.

Actinomycin-D is marketed under the trade name Dactinomycin. It binds to DNA duplexes, thereby interfering with the action of enzymes engaged in replication and transcription. Actinomycin-D is one of the older chemotherapy drugs which has been used in therapy for many years. It is a clear, yellow liquid which is administered intravenously and most commonly used in treatment of a variety of cancers.