A new antitumor antibiotic, 13-deoxycarminomycin, has been isolated from the anthracycline complex produced by Streptomyces peucetius var. carminatus (ATCC 31502), a biochemical mutant of Streptomyces peucetius var. caesius, the doxorubicin-producing microorganism. The new anthracycline, showing antibacterial and cytotoxic activity in vitro, was found active against P-388 murine leukemia.