Several bacterial strains utilizing crude oil as their sole carbon and energy source were isolated from marine environment polluted by crude oil. Among them, the selected strain 4A3 showed strong degradation activity for crude oil. This strain was identified as a Provindencia rettgeri 4A3 based on the morphological, biochemical, and physiological characteristics. The optimum cultural conditions was as follows; 26$^{circ}C$ for temperature and 7.0 for initial pH. Additionally, the optimal concentration of sodium chloride was 2.0%, indicating that this strain was derived from sea water. The emulsifying activity of 4A3 was the highest after 3 days of cultivation under the condition of 2.0% sodium chloride, pH 7.0 and 26$^{circ}C$. This strain had one cryptic plasmid in 7.0kb size.