The thermal characteristics of a styrene-epsilon-caprolactone diblock copolymer, P(S-b-CL), in blends with poly(vinyl methyl ether) (PVME) were studied by DSC. The glass transition temperatures show that PVME is only dissolved in the PCL block. It segregates from the PCL block at low temperatures. The addition of PVME leads to increasing crystallinity of the PCL block in a certain range of composition. However, degrees of crystallinity do not change significantly with crystallization temperature. Optical inspection revealed that the PCL block does not form spherulites. The crystallization kinetics of the PCL block has been systematically studied. The rate constants of crystallization for different blends decrease exponentially with crystallization temperature, whereas the rates of crystallization are scarcely affected by PVME content. The Avrami exponents were found close to two.