Biodegradable poly(L-lactic acid) (PLLA)/graphene oxide (GO) nanocomposites have been prepared successfully at various GO loadings. Transmission electron microscopy and wide angle X-ray diffraction results indicate that a relatively fine dispersion of GO is achieved in the PLLA matrix. Nonisothermal melt crystallization peak temperatures are slightly higher in the nanocomposites than in neat PLLA. The overall isothermal melt crystallization rates are reduced for both neat PLLA and the PLLA/GO nanocomposites with increasing crystallization temperature; moreover, the overall isothermal melt crystallization rates are significantly greater in the nanocomposites than in neat PLLA although the crystallization mechanism remains unchanged. The crystal structure of PLLA is not modified in the PLLA/GO nanocomposites. Both the nonisothermal and isothermal melt crystallization of PLLA in the nanocomposites are influenced apparently by the GO loading. (C) 2011 Elsevier B.V. All rights reserved.