Commercially available organosilane (3-glycidoxypropyltrimethoxysilane (GPTMS)) coupling agent was used to treat talc in order to improve the affinity relative between the filler and the polymer in composites as well as filler and polymer in the thermoplastic polyurethane/polypropylene (TPU/PP) blends (talc content was 5 wt%). The talc particles were first modified with GPTMS and then introduced into TPU, PP as well as TPU/PP blends with different weight ratios of polymers using blending method and subsequently injection molded in a hydraulic press. The aim was to report the effect of silane coupling agent on the thermal and morphological properties of talc filled composites and blends. The results showed that the thermal properties of the TPU, PP composites and TPU/PP blends were improved with the addition of silane treated talc (higher melting (T-m), crystallization (T-c) temperatures and degree of crystallinity (chi(c))). The glass transition temperature (T-g) obtained by dynamic mechanical analysis (DMA) of the TPU soft segments in TPU/PP blends increased with the addition of untreated and silane treated talc due to lower mobility of the soft segments in TPU and better miscibility of TPU and PP. TPU/PP blends with the silane treated talc show better thermal stability than the TPU/PP blends with untreated talc. (c) 2014 Society of Plastics Engineers