AIM: To understand the correlation of serum cholinesterase (CHE) activity with gastric cancer and to assess their clinical significance.METHODS: The velocity method was adopted to detect the activity of serum CHE in patients with gastric cancer and in patients with non-malignant tumor as controls.RESULTS: The serum CHE activity in the treatment group was significantly lower than that in the control group with a very significant difference between the two groups (83.3:113.1,P = 0.0003). Age was significantly associated with the incidence of gastric caner.CONCLUSION: Serum CHE activity has a close relation with the incidence of gastric cancer.