Biosurfactants are microbial surface active compounds with both a hydrophilic and hydrophobic regions in their structures. From marine water, sand and sediment samples taken from different sites along Vietnam coast (Ha Long Bay, Cat Ba island, Nghi Son, Hue, Quang Nam, Vung Tau, Binh Thuan and Ben Tre), 28 types of bacteria, 'which are able to produce MosurJactants were isolated. The results of study on physiological characteristics. API kit testing and 16S rRNA analyses showed that the strains which produce biosurJactants differently include Ochrobactrum cytisis CBI c1, Bacillus megatherium CBI c2. Janibacter marinus CB2a, Acinetobacter haemolyticus NS5a. Acinetobacter calcoaceticus QN15, Acinetobacter soli H1, Acinetobacter calcoaceticlls H3, Pseudomonas pseudomalei H24, Pseudomonas aeruginosa H33, Bacillus subtilis N1. Rhodococcus ruber 4C3, Acinetobacter junii 6C1. Leuconostoc sp. 6C3, Pseudomonas sp. HP55, Rhodocdccus ruber TD2, Ochrobactrum pseudogrinonense BD2. Among them, the ones that are capable to highly produce biosurfactants (15- 35g/l) were selected.. Their biosurfactant producing capacity with oil emulsification index (E24). oil replacement reached to 70-100 percent. 60-100 percent. respectively. Optimal substrate for their growth were DO, olive oil, and molasses. Their optimal growth condition was pH: 7-8, temperature: 30-31°C and NaCI: 1-3 percent. The results oj NMR and GC-MS analyses showed that biosurJactants were extractedfrom bacteria strains HP55 and TD2, 6C1 belong to rhamnolipid and long-chain Jalty acid grollps. respectively. Results oj toxicity test confirm that biosurfactant produced by the studied marine microorganisms were safe to be used in some industries and for environmental treatment.