This work presents the preparation and characterization of compression‐moulded montmorillonite and carbon nanofibre‐polypropylene foams. The influence of these nanofillers on the foaming behaviour was analyzed in terms of the foaming parameters and final cellular structure and morphology of the foams. Both nanofillers induced the formation of a more isometric‐like cellular structure in the foams, mainly observed for the MMT‐filled nanocomposite foams. Alongside their crystalline characteristics, the nanocomposite foams were also characterized and compared with the unfilled ones regarding their dynamic‐mechanical thermal behaviour. The nanocomposite foams showed higher specific storage moduli due to the reinforcement effect of the nanofillers and higher cell density isometric cellular structure. Particularly, the carbon nanofibre foams showed an increasingly higher electrical conductivity with increasing the amount of nanofibres, thus showing promising results as to produce electrically improved lightweight materials for applications such as electrostatic painting.