A total of 70 actinomycetes strains were isolated from dams and caves of Hadhramout –Yemen and screened for their anti-bacterial activity based on their color and activity against bacterial pathogens. Twenty isolates have shown activities against pathogenic bacteria. Fourteen isolates (70%) showed activity against Bacillus subtilis by agar disk diffusion, twelve isolates (60%) showed activity against Staphylococcus aureus and fifteen isolates (75%) showed activity against Pseudomonas aeruginosa. The activity was minimal against Escherichia coli, having only 8 isolates (40%). Nine isolates were highly active with an inhibition zone more than 25 mm in diameter. Most of the isolates inhibited growth of tested Gram negative and Gram positive bacteria.