This study was conducted to develop an HPLC method for determining vitamin B$_{12}$ in fortified foods which has typically been determined by microbiological assays according to AOAC and Korean Food Code approved methods. Vitamin B$_{12}$ (cyanocobalamin) was determined by reversed-phase HPLC with a triple column and UV/VIS dectector (550 nm) using the column switching technique after extraction with 5 mM potassium phosphate solution by sonication without a clean-up procedure. The recovery of spiked samples and limit of detection (LOD) by HPLC were 78.6 ∼107.5 % and 2 ppb ($mu extrm{g}$/kg), respectively. The LOD of the microbiological assay (MBA) was much lower than that of HPLC. The concentrations of vitamin B$_{12}$ analyzed in all tested samples (n=12) confirmed compliance with declared label claims. The range of recovery ratio by the HPLC method when compared to the microbiological assay was 76.2 ∼140.0 %. There was not significant difference between the HPLC and MBA methods (p < 0.01) with r=0.9791 and linear regression y=0.9923x-0.04. The HPLC method for determining vitamin B$_{12}$ using the column-switching technique appears to be suitable for determining vitamin B$_{12}$ concentrations above 1 $mu extrm{g}$/100 g in fortified foods.ied foods.