The present work is concerned with the effect of processing variables and filler concentration on the electrical conductivity, hardness, and density of composite materials prepared by compression molding of a mixture of zinc powder and nylon 6 powder. The electrical conductivity of the composites is < 10(-12) S/cm, unless the metal content reaches the percolation threshold at a volume fraction of about 0.18, beyond which the conductivity increases markedly by as much as 10 orders of magnitude. The density of the composites was measured and compared with values calculated by assuming different void levels within the samples. Furthermore, it is shown that the hardness increases with the increase of metal concentration, but for values of filler volume fraction higher than about 0.30 the hardness of samples remains almost constant. Two parameters of molding process, temperature and time, were shown to have a notable effect on the conductivity of composites, whereas pressure has no influence on this property in the pressure range considered.