The separation of six water-soluble vitamins (e.g., B-1-thiamine, B-2-riboflavin, B-3-nicotinic acid, B-6-pyridoxine, B-12-cyanocobalamin, and C-ascorbic acid) was investigated using capillary electrophoresis. Initially, the most important variables in micellar electrokinetic capillary chromatography were established, such as: background electrolyte pH; surfactant concentration; detection wavelength; applied voltage, and amount of organic modifier. The solutes were separated within 8 min, with excellent efficiency (3 (.) 10(5) theoretical plates) and resolution, which means great advantage towards the analysis of real samples. Two pharmaceutical samples were analyzed using the optimized method, which was shown to be adequate for this purpose.