Micellar electrokinetic capillary chromatography (MECC) was applied to the determination of water-soluble vitamins (WSV) in pharmaceutical preparations. The analytical procedure employed in the WSV separation by MECC showed a satisfactory average column efficiency (195,000 N) and resolution (more than 100 theoretical peaks separable). The mean reproducibility in the retention time of consecutive and day-to-day runs was 1.1% and 5.1%, respectively. Analyses were performed after extraction of active ingredients by solid phase extraction. Recoveries (92-103%) and relative variation coefficients (less than 5%) confirmed the potential of MECC in the field of pharmaceutical analysis.