Abstract: Objective: To investigate the expression of signal transducer and activator of transcription 3 (STAT3)and p38 in gastric cancer and to evaluate the relationship between the expression of these two indices and the histologicaldifferentiation grades. Methods: PV6000 Polymer Detection System For Immunohistological Staining was used to detectthe expression of STAT3 in 60 cases of gastric cancer (30 cases in the highly-to-moderately differentiated cancer group,30 cases in the poorly differentiated cancer group) and 30 samples of normal stomach tissue. Results: The expression ofSTAT3 and p38 was higher in gastric cancer tissues than in normal stomach tissues(P<0.01). The expression of STAT3 andp38 in the highly-to-moderately differentiated cancer group was higher than in the poorly differentiated cancer group, witha statistically significant difference (P<0.01). A correlation between STAT3 and p38 was found. Conclusion: The expres-sion of STAT3 and p38 in gastric cancer tissues, especially in poorly differentiated cancer tissues is high. The abnormalactivation of STAT3 and p38 may play an important role in the occurrence and development of gastric cancer.