The electrical contact resistance between isolated pairs of micron-sized gold particles has been measured as a function of their separation using apparatus constructed in house. When incorporated into a percolation model for current transport in a conducting particle filled insulator, the results of such measurements have been shown to be consistent with the observed variation of conductivity with filler content beyond the percolation threshold in gold filled epoxies. This has been tested further by using adsorbed alkanethiol monolayers to control the interparticle spacing in the composites, demonstrating the importance of the contact resistance for the macroscopic current transport properties.