This paper presents composites of polycarbonate (PC) having different amounts of multiwalled carbon nanotubes (MWNT). The composites were prepared by diluting a masterbatch of PC with 15 wt% MWNT using melt mixing in a DACA-Micro Compounder. Electrical resistivity measurements indicated percolation of MWNT between 1 and 1.5 wt%. Transmission electron microscopy (TEM) showed excellent dispersion of the MWNT and indicated no preferred orientation of MWNT in extrusion direction. In addition, a conductive PC-2 wt% MWNT composite was melt mixed with polyethylene in order to get co-continuous blends exhibiting double percolation. Significant reduction in electrical resistivity of the blends could be achieved in compositions down to 30 vol% filled PC in which the total MWNT content was only 0.41 vol%. These blends exhibited co-continuous structures.