The electrical resistivity and morphology of polypropylene/nylon (PP/Ny) immiscible blends incorporated with carbon black (CB) were studied. CB was found to be preferentially located in the Ny phase or upon the Ny/PP interface. Blends with a co-continuous phase morphology depicted especially low resistivity values, due to a “double percolation” effect. The blend preparation sequence tends to affect the phase morphology, thus influencing the system's resistivity. Polymer polarity and crystallinity are important factors determining the blend's morphology, which relates directly to the electrical resistivity obtained.