Capillary isotachophoresis was employed to determine dimethindene in various dosage forms. Several electrolyte systems of varying compositions and varying pH were tested. For validation of the method and the determination of dimethindene in real samples (gel, drops, capsules), two electrolyte systems were selected. Precision, correctness, linearity, robustness, and selectivity of the ITP method were evaluated for both electrolyte systems. The pre-treatment of the sample prior to analysis consisted in dissolving and diluting the pertinent dosage form containing dimethindene with demineralized water to the required concentration. The sample adjusted in this way was directly dosed into the apparatus.