Pantomycin is a new antibiotic isolated from a group of antibiotics produced in fermentation cultures of Streptomyces hygroscopicus. Pantomycin is a triad composed of carbohydrate, lipid and polypeptide moieties and is obtained by a series of extractions from homogenized cells with organic solvents. It is purified by selective elution from a Sephadex gel column with 48% ethanol. The purified antibiotic exhibits anti-fungal activity against 1 animal and 73 plant pathogens. It displayed anti-bacterial activity against 9 plant and 7 human pathogens and 1 saprophyte. Pantomycin inhibited Newcastle disease virus, vesicular stomatitis virus and vaccinia virus.