To investigate the oil degrading properties of psychrotrophic bacterium Acinetobacter calcoaceticus Al-l the effects of environmental factors on this bacterium were studied. The optimal environmental conditions for cell growth rate and oil-emulsifying activity were as follows; temperature $15^{circ}C$, pH 7.5, salt concentration 0- 3% and crude oil concentration 0.1%. Additionally the optimal concentration of Nand P source for cell growth rate and oil-emulsifying activity were 0.76 mM and 0.057 mM as $(NH_4)HS0_4$ and $K_2HP0_4$, respectively. Analysis of remnant oil by gas chromatography showed time dependent oil degradation pattern by A. calcoaceticus during cultivation; At lOoe and $15^{circ}$e, most alkane peaks were disappeared and it showed large quantities of crude oil were degraded. But at $25^{circ}$e alkane compounds in the crude oil were partially degraded even after 120 hours incubation.