Streptomyces verticillus, cultured in a medium composed of soybean meal, glucose, millet jelly, corn steep liquor and mineral salts, produces bleomycin A2 and B2 (two major components) and other minor components, with eleven bleomycins (A1-A6, B1-B6) reported initially. Six new bleomycin components were isolated from a copper-chelated bleomycin mixture (Lot No. B-66019 F1, manufactured by Nippon Kayaku Co. Ltd.) using CM-Sephadex C-25 column chromatography (developed by a linear gradient of ammonium formate), Dowex 50W X4 column chromatography, and repeated CM-Sephadex C-25 column chromatography. The new components include demethyl A2 (eluted from 0.20~0.24m ammonium formate, negative ninhydrin and Sakaguchi reactions), B/ (eluted from 0.25~0.27m ammonium formate, negative Sakaguchi reaction), A2'-a and A2'-b (from the fraction between A2 and B2, positive ninhydrin and negative Sakaguchi reactions, separated by three rounds of CM-Sephadex C-25 chromatography), B6 (eluted from 0.93~0.98m ammonium formate, positive Sakaguchi and negative ninhydrin reactions, differentiated from B5 by paper chromatography), and A2'-c (from another bleomycin mixture batch, strongly positive Pauli reaction, negative ninhydrin and Sakaguchi reactions). Their properties including chromatographic behavior (on silica gel G, Avicel SF, and paper chromatography) and antimicrobial activity (measured by the cylinder-agar plate method) are presented in Table 1, and their chemical structures will be detailed in a succeeding report.