Abstract: This process for making antistatic filaments utilizes a specific mixture of compounds in order to suffuse electrically conductive particles into a filamentary polymeric substrate by forwarding the substrate through a grooved roll-type mix applicator. The mixture comprises a dispersion of the electrically conductive particles in liquid solvent which is a mixture of formic acid and a member selected from the group consisting of an amide, a carboxylic acid other than formic acid, an alcohol, an ester, a ketone, an ether, and a hydrocarbon. The process provides advantages over the prior art in permitting the use of high processing speeds, enabling easy stringup, and allowing the use of knotty and/or slubby filamentary substrates.