Biodegradable poly(epsilon-caprolactone) (PCL)/polyhedral oligomeric silsesquioxanes (POSS) nanocomposites at various POSS loadings were prepared via solution casting method in this work. Scanning electron microscopy observation indicates that POSS are homogeneously dispersed in the PCL matrix. The experiments show that the crystallization peak temperature is higher in the nanocomposites than in neat PCL during nonisothermal melt crystallization; moreover, the overall crystallization rate is faster in the nanocomposites than in neat PCL during isothermal melt crystallization. Both nonisothermal and isothermal melt crystallization studies suggest that the crystallization of PCL is enhanced by the presence of POSS and influenced by the POSS loading. The effect of POSS on the crystallization is twofold: the presence of POSS may provide heterogeneous nucleation sites for the PCL crystallization while the aggregates of POSS may restrict large crystal growth of PCL. However, the crystallization mechanism and crystal structure of PCL remain almost unchanged despite the presence of POSS in the nanocomposites. POLYM. ENG. SCI., 51:2159-2165, 2011. (C) 2011 Society of Plastics Engineers