Biodegradation behavior of poly(butylene succinate-co-butylene adipate) (PBSA) was examined when PBSA was buried in the natural soil and the soil inoculated with Burkholderia cepacia after sterilization. After 80 days of the soil burial test at room temperature, the PBSA film buried in the natural soil lost 34.0% of its intial weight, while the same film lost 59.2% of its initial weight when buried in the sterile soil inoculated with B. cepacia. The optical and SEM observations of the surface morphology of the PBSA film also indicated that the surface erosion and rupture took place faster when the film was buried in the sterile soil inoculated with B. cepacia compared to the film buried in the natural soil. Viable cell number in the natural soil and that the sterile soil inoculated with B. cepacia increased by a factor of 6~7 and 10~14, respectively as compared to the initial viable cell number.