In this study, biosurfactant producing bacteria were screened from oil-contaminated areas in Bangkok and vicinities, Thailand. Isolated bacteria of 1,094 isolates were collected from the samples. Primary screening of biosurfactant producing bacteria was performed by oil agar plate method. From primary screening, 82 isolates showed dispersion zone surrounding colonies. Ten isolates with the highest RZC values were selected to study in the secondary screening. These isolates were separately cultured in NB. Tensiometer was used to measure surface tension of each cell free cultured broth. The decreasing of surface tension was observed in 4 isolates. BKG 04-005 isolate showed the lowest surface tension value of 18.58mN/m. According to the results, biosurfactant of BKG 04-005 was growth-associated product. To obtain biosurfactant, its cell free cultured broth was acidified and extracted by acid and a mixture of chloroform: methanol, respectively. The chemical structure of crude biosurfactant was identified as a lipopeptide by FTIR spectroscopy.