Objective: To initially explore the application of proteome technologies in study of serum, to establish two-dimen-sional gel electrophoresis (2-DE) profiles of human gastric cancer serum and paired normal serum, and to screen and identify differentially expressed proteins in poorly-differentiated gastric cancer serum and paired normal serum, in which try to find out significant biomarker candidates for gastric cancer. Methods: 2-DE was adopted to separate the total proteins of poorly-differentiated gastric cancer serum and paired normal serum. After staining and analyzing by ImageMaster 2D Elite software, the differentially expressed proteins were identified by matrix-assisted laser desorption/ionization-time of flight- mass spectrometry (MALDI-TOF-MS). Results: 2-DE serum profiles with high resolution were obtained. Five protein spots were found as differentially-expressed proteins and identified as Serpin B6 (Placental thrombin inhibitor) Cytoplasmic antiproteinase (CAP) (Protease inhibitor6) (PI-6), Septin-1 (LARP) (Serologically defined breast cancer antigen NY-BR-24), Kallikrein-6 precursor (Protease M) (Neurosin) (Zyme) (SP59), Hemoglobin beta chain, Hemoglobin beta chain and Beta-defensin 108 precursor (Beta-defensin 8) (DEFB-8). Conclusion: The differential proteins were demonstrated to present in poorly-differentiated gastric cancer serum and paired normal serum. The molecular biomarkers associated with poorly differentiated gastric cancer could be possibly identified by the high throughput screening proteome technology. Objective: To explore explore the application of proteome technologies in study of serum, to establish two-dimen-sional gel electrophoresis (2-DE) profiles of human gastric cancer serum and paired normal serum, and to screen and identify differentially expressed proteins in poorly -differentiated gastric cancer serum and paired normal serum, in which try to find significant markers for gastric cancer. Methods: 2-DE was separated to the total proteins of poorly-differentiated gastric cancer serum and paired normal serum. After staining and analyzing by ImageMaster 2D Elite software, the differentially expressed proteins were identified by matrix-assisted laser desorption / ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Results: 2-DE serum profiles with high resolution were obtained. Five protein spots were found as differentially-expressed proteins and identified as Serpin B6 (Placental thrombin inhibitor) Cytoplasmic antiproteinase (CAP) (Protease i (Ser-defined breast cancer antigen NY-BR-24), Kallikrein-6 precursor (Protease M) (Neurosin) (Zyme) (SP59), Hemoglobin beta chain, Hemoglobin Conclusion: The differential proteins were demonstrated to present in poorly-differentiated gastric cancer serum and paired normal serum. The molecular biomarkers associated with poorly differentiated gastric cancer could be possibly identified by the high throughput screening proteome technology.