The effect of a two-phase electrolyte on diffusion of reactants to a horizontal planar electrode in quiet solution was investigated. Three systems were studied; ferricyanide reduction from basic aqueous solution, ferricyanide reduction from basic aqueous solution with an inert drop of methylene chloride on the electrode, and iodine reduction from aqueous solution with a drop of methylene chloride containing a high concentration of iodine on the electrode. Experiments were conducted with controlled variation of reactant concentration, drop size, number of drops, and electrode area. It was found that with the addition of an inert drop, the reaction rate decreased proportionally to the drop contact area, while the reaction rate increased substantially with the addition of a drop containing a high concentration of iodine.