The cultivation of Streptomyces coeruleorubidus produced an anthracycline antibiotic complex with daunorubicin (rubomycin C) as the main component. The complex was isolated from the culture broth by chloroform extraction, and fifteen antibiotics were separated via Kieselgel 60 column chromatography (developing with chloroform-MeOH with gradually increased MeOH concentration from 1% to 20%) and preparative silica gel TLC (using chloroform-benzene-MeOH systems). Seven were identified as known anthracyclines (daunomycinone, daunorubicin, bisanhydrodaunomycinone, 7-deoxy-13-dihydrodaunomycin, baumycins A and C, 13-dihydrodaunomycinone) using NMR and HPLC. Two new antibiotics (rubomycins F and H) with activity against Gram-positive bacteria were isolated. Their physicochemical properties (MP, UV, IR, FD-MS) were determined: Rubomycin F had MP 145~148°C (dec), UV peaks at 482, 495, 534 nm, IR bands at 3400, 1720, 1625, 1558 cm⁻¹, and FD-MS m/z 600 (M+H)⁺ (C₃₀H₃₄NO₁₂); Rubomycin H had MP 163~166°C (dec), UV peaks at 482, 495, 534 nm, IR bands at 3450, 2860, 1625, 1585 cm⁻¹, and FD-MS m/z 586 (M+H)⁺ (C₂₉H₃₂NO₁₂). Acid hydrolysis of both gave daunomycinone. ¹H NMR spectra suggested their structures (1 for F, 2 for H). Rubomycin H's structure was confirmed by synthesis from daunorubicin (yielding 3'-N-carbomethoxyrubomycin C, identical to natural H). Thus, rubomycins F and H are new natural anthracycline antibiotics.