Cyclamidomycin is obtained from the culture filtrate of Streptomyces sp.MA130-A1. It inhibits the growth of Gram-positive and Gram-negative bacteria and shows inhibition of nucleoside diphosphate kinase of Escherichia coli .It inhibits plaque formation of male-specific coliphages and suppress the multiplication of both RNA phage Qβ and filamentous DNA phage f1 at the concentration of 3. 13-6. 26 μg/ml.