Linear low-density polyethylene (LLDPE) possesses better mechanical properties compared to low density polyethylene (LDPE), but it has poor melt strength, which is needed in foam and film processes. This work presents a new and promising approach to improve the melt strength of LLDPE through incorporation of nanofibrillar polyamide 6 (PA6) and also nanofibrillar polyethylene terephthalate (PET) into the LLDPE matrix. It will be shown that the melt strength and mechanical properties of the blends can be tuned through controlling the size of the fibrils and morphology of the blends. The effect of the nanofibrillated PA6 and nanofibrillated PET on the melt strength and flow ability of the LLDPE are characterized through rheological analysis. The differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) are respectively used to analyze the crystallinity and foam characteristics of the blends. It will be shown that the melt strength and foaming ability of LLDPE/nanofibrillated PA6 and LLDPE/nanofibrillated PET blends are markedly improved compered to pure LLDPE and the LLDPE/PA6 and LLDPE/PET blends with dispersed PA6 or PET islands.