AM-2282, a new alkaloid has been isolated from cultures of Streptomyces sp. AM-2282 by solvent extraction and silica gel chromatography. The compound exhibits a strong absorption maximum at 292 nm and shows antimicrobial activity against fungi and yeast. The LD50 of its hydrochloride (i.p. in mice) is 6.6 mg/kg. The molecular formula of AM-2282 has been determined as C28H26N4O3. The producing strain, AM-2282 was classified as a new species and the name, Streptomyces staurosporeus AWAYA, TAKAHASHI and OMURA, nov. sp. is proposed.