A maleic anhydride grafted thermoplastic elastomer (TPEg) was prepared. The effect of the TPEg on the morphology and performance of polypropylene (PP)/polyamide 6 (PA-6) blends was studied. The final properties of the blends were tuned through variations in the TPEg/PA-6 ratios and TPEg and PA-6 percentages in the blends. Scanning electron micrographs showed that the TPEg greatly improved the homogeneity of the blends, and this led to better mechanical performance. The nonisothermal crystallization behaviors of PP and PA-6 in the blends, revealed by differential scanning calorimetry, were different from those of pure PP and PA-6. The crystallization temperature and rate of PP were promoted by the PA-6 component because of its nucleating effect, whereas stepwise crystallization was detected for PA-6 in the PP/PA-6 blends when the TPEg was added. On the basis of these observations, a schematic model was proposed for these blends. (C) 2003 Wiley Periodicals, Inc.