The effects of a cyclodextrin (alpha-CD) on the crystallization of poly(butylenes adipate) (PBA) were studied in this work. Depending on the rate of cooling from the melting state, pure PBA shows a polymorphic crystallization behavior. That is, when the cooling rate is slow, PBA forms dominantly the (x-form crystal and the peak crystallization temperature is above 33 degrees C. In contrast, when the cooling is rapid, it forms dominantly the beta-form crystal and the peak crystallization temperature is below 33 degrees C. The crystallization behavior of PBA is almost not affected by the introduction of pure a-CD. However, the inclusion complex between PBA and alpha-CD (PBAIC) can effectively enhance the crystallization of PBA. By introduction of PBAIC, the crystallization rate of PBA is greatly accelerated and full alpha-form crystal of PBA is preferentially formed at temperature higher than 28 degrees C.