The vertical profiles of electron distribution near the low and mid-geomagnetic latitudes have been investigated by the computerized tomography method using Algebraic Reconstruction Technique (ART). The slant total electron contents (STEC) data for ionospheric tomography were measured at a regional GPS reference network of nine stations that have been operated by Korea Astronomy and Space Science Institute (KASI). The results from tomographic reconstruction method are in good agreement with profiles obtained by Ionosonde near the KASI GPS stations. The electron density profiles reconstructed by the tomographic method were compared with the results from Ionosonde and IRI-2001 model. GPS tomography reconstruction