Pyrindamycin A is an antibiotic produced by the strain of Streptomyces spp. It inhibits DNA synthesis and has the activity against gram-positive and gram-negative bacteria. It has antitumor activity against murine leukemia, shows stronger cytotoxic activities towards murine and human tumor cell lines and especially towards doxorubicin-resistant cells, inhibits P388 and P388/ADR cells with the same IC50 of 3.9 μg/ml.