Dnacins A1 and B1, new basic antibiotics with strong and broad antibacterial activities, were isolated as dark red or reddish brown needles from the culture broth of Nocardia sp. No. C-14482. The characteristic absorption maxima at 213 nm, 281 or 283 nm and 496 nm in the UV and visible range and other physicochemical properties indicated that dnacins A1 and B1 are novel antibiotics which belong to the group having aminobenzoquinone moieties.