A new streptothricin family antibiotic producing Streptomyces spp. SNUS 8810-111 was isolated from a soil sample. Study of its morphological and physiological characters indicated that the antibiotic producing organism was a Streptomyces spp. Taxonomical studies suggested that the organism might belong to the genus Streptomyces gougeroti. The organism produced antibiotics most in calcium carbonate-tryptic soy broth. The active principles were recovered from the broth with a cation exchange resin and eluted from the resin with HCI. Cellulose column chromatography gave two active principles. 1H-1H Homo-COSY study on the first compound revealed four structural components. Total hydrolysis of the antibiotic with HCI allowed isolation of β-lysine. From these data the antibiotic was found to be streptothricin D. The other compound showed one additional signal in the 1H NMR and the 13C NMR spectra. The signal was from a methyl group attached to a nitrogen atom. Comparison of the NMR signals with those of streptothricin D suggested that the compound was N-methylstreptothricin D which was a new compound in the family of streptothricin antibiotics.