A proteomic map of Hanwoo loin was obtained using 2-D SDS-PAGE and mass spectrometric analysis: 27 bovine proteins plus 2 proteins having similarities to other mammal proteins out of 52 proteins analyzed. The identified proteins consisted of 50 % basic house keeping proteins involved in metabolism, 30% muscle proteins, and other miscellaneous proteins. Many proteins on the 2-D gel with different molecular weights and isoelectric points were identified as same proteins due to posttranslational modification. As many of the identified house keeping proteins showed the high sequence similarities to other mammal equivalent proteins, searching the mammal databases could confirm the annotation. The preliminary identification of the proteome in bovine loin tissue could reveal the functions of proteins at over 50 % of chance with high fidelities. Using the established loin proteome map, proteomic difference between 1 yr and 2 yr Hanwoo loin tissues were compared on 2D gel. Regardless of the difficulty normalizing protein concentrations and sample-to-sample variations, three unidentified proteins and myoglobin were selected as up-regulated proteins during the fat deposition period. This study contributes to a move thorough and holistic understanding of beef meat, helping to build the basis for future identification of new markers for good quality meat.