The theory of isotachochromatography has been verified and proved to be essentially correct. Acetate was used as a leading buffer and mostly serine as a terminal buffer to separate acids with pKa values intermediate between those of the leading and terminal buffers on a column of Dowex 50W-X2. Separation could be effected. The length of a zone was proportional to the amount applied. The pH levels of the plateaux differed by values equal to the difference in the pKa values of the components as demanded by theory.