Capillary electrophoresis (CE) with two types of contactless conductivity detector, with semitubular or tubular electrodes, was employed for the determination of selected cations in mineral waters and in procaine infusion solutions. First the composition of the background electrolyte (BGE) was optimised with respect to the noise and signal/noise ratio of the detectors. Additions of tensides (hexamethonium bromide, sodium dodecyl sulfate) to the BGE had a positive influence on the noise characteristics of the detectors. The optimised CE separation conditions were applied to the analysis of real samples, particularly for the determination of calcium and magnesium ions in mineral waters (Mattoni and Magnesia) and for the determination of sodium, potassium, calcium and procaine hydrochloride ions in the infusion solutions. The differences between the determined and declared calcium and magnesium concentrations in the mineral waters ranged between 11 and 16 % and the concentrations of ionic components in procaine solutions between 3 and 7 %.