Abstract: We isolated 224 actinomycetes strainsfrom sea mud samples and 32 strainsfrom seawater samples of the Jiaozhou Bay, China,by using the spread method1 The isolates were grouped into 7 groups on basis of their morphological characteristics1 Their antimicrobial activities were tested by using the cup-plate method, and the results showed that 7% of the isolates were active against Staphylococcus aureus, 11% against Sarcine lutea, 10% against Escherichia coli, 11% against Bacillus pyocyaneus, 2% against Candida albicans, 5% against Cryptococcus, 6% against Streptomyces viridochromogenes, and 6% against Mucor miehei1 Twenty-two percent of isolates were active against at least one of the test organisms1 Our data suggests that actinomycetesfrom the Jiaozhou Bay, China can produce various active metabolites against pathogenic microorganisms, which provids unique and plentiful sources to screen novel natural products for combating diseases in man1