This study is to examine the effect of hydrophilicity on the biodegradability of the plasma treated polymers. Poly(butylene succinate) films and biodegradable aliphatic polyesters were exposed to low-temperature oxygen plasma under various conditions. Surface-hydrophilicity of the plasma treated samples were evaluated by water-contact angle, moisture regain, and FT-IR analysis. Their biodegradabilities were determined by the activated sludge test, soil-burial test, and enzyme hydrolysis, while the surface morphology changes of the degraded specimens were observed using the scanning electron microscope. Plasma treated films were found to have some voids and cracks on their surfaces, which resulted from physical etching as well as chemical activation by the introduction of polar groups. From the results of contact angle, moisture regain, and FT-IR analysis, it was shown that the suitable oxygen plasma treatment can enhance surface hydrophilicity without loss of bulk strength. Biodegradability of plasma treated samples increased remarkably due to the high surface hydrophilicity of PBS. Therefore, it can be concluded that the appropriate oxygen plasma treatment enhances both surface hydrophilicity and biodegradability, while the plasma treated PBS maintains its original bulk properties.