Summary: The present paper deals with the effects of natural weathering on the properties of poly(propylene)/polyamide-6 blends (70/30 wt %) without and with PP-g-MA used as the compatibilizer at various content ratios (2, 4 and 6 wt%). The resulted changes in the chemical structure, morphology and mechanical properties of the different blends were analyzed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and tensile tests. After one year of outdoor exposure, no important changes in the chemical structure are observed by FT-IR spectroscopy for both virgin and compatibilized blends. SEM analysis revealed the effectiveness of PP-g-MA to improve the compatibility of PP/PA-6 blends. However, the weathering effect on the morphology of both virgin and compatibilized blends resulted in the formation of voids and cracks on the fracture surfaces, while the ultimate tensile properties decreased considerably. The overall results indicated clearly that the presence of PP-g-MA compatibilizer in PP/PA-6 blends had no influence on the photo-oxidation process.