A method is described for measuring the electroosmotic flow of highly concentrated electrolyte solutions. The method relates bulk movement to the transport of an ion's water of hydration and to the heat produced by the Joule effect; it also facilitates studies of electrode reactions conducive to electroosmotic migration at high concentrations. Data are presented on the bulk flow rates of CaCl//2, SrCl//2, BaCl//2, and HCl solutions as a function of concentration and composition of the finely divided packing. An analysis of these relationships shows that the electroosmotic flow of solutions occurs up to a concentration of 2-4 N, which considerably exceeds the literature data on the concentration limits necessary for such migration.