The electrical conductivity of capillary electrochromatography (CEC) columns packed with macroporous particles has been investigated. Columns were prepared with commercially available octadecylsilane-coated 7 mum diameter particles (Nucleosil) having nominal pore diameters of 100, 300, 500, 1000, and 4000 Angstrom, and operated under typical CEC conditions. The conductivity of the 100 iq column was in agreement with that predicted from theory for nonporous spheres, indicating that intraparticle current was negligible. Columns packed with the wide-pore media (1000 Angstrom and 4000 Angstrom), in contrast, yielded conductivity values over 2-fold greater than the 100 Angstrom. The electroosmotic contribution to current flow in these columns was deemed insignificant on the basis of theoretical modeling and the experimental data. It was therefore concluded that the increased column conductivity of the wide-pore packed columns was the result of intraparticle current transport. These results further suggest that wide-pore packings are more permeable to fluid flow and thus can provide maximum gains in efficiency due to electroosmotic perfusion when electrical double layer thickness is small relative to the median pore diameter of the packing.