Two procedures for separation and determination of vitamin B12in multivitamin tablets by reversed phase high performance liquid chromatography are proposed. Sample preparation is very simple: tablets are dissolved in distilled water, centrifuged and filtered. The sample solution is directly applied in the sample loop injector and chromatograms are obtained with gradient elution using water-methanol and water-acetonitrile as solvents. The peak of vitamin B12from samples of B-complex tablets is well separated with the two procedures. For multivitamin tablets, however, only the procedure with water and methanol as solvents was good for separation and quantification of vitamin B12. Both procedures were verified by the standard addition method and also compared to a previously developed method using electrothermal atomic absorption spectrometry for vitamin B12determination.