AIM: To investigate the expression and pathological factors of Angiopoietin-2 (Ang-2) in primary gastric cancers and adjacent normal tissues.METHODS: The expression of Angiopoietin-2 and VEGF were studied in 72 primary gastric cancers and adjacent normal tissues from the same patients by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR)and immumohistochemistry.RESULTS: Ang-2 was mainly expression in tumor cells.There were significantly difference between expression of Ang-2 in primary gastric cancer and in adjacent normal tissue samples (P=0.003). It was statistically correlation between Ang-2 and VEGF expression in tumors (P=0.0055).With regard to Ang-2 expression in tumors, there were significant difference between early stage and advanced stage (P=0.017), and significant difference between positive vascular involvement and negative vascular involvement (P=0.032). However, there was no significant difference between moderate-poor differential type and high differential type (P=0.908), between positive lymph node metastasis and negative lymph node metastasis (P=0.752),between positive serosal invasion and negative serosal invasion (P=0.764). The cases with expression of Ang-2 were increasing with advanced stage and vascular involvement.CONCLUSION: The results manifested that Angiopoietin2, coordinated with VEGF, play role in regulating tumor angiogenesis of gastric cancer.