Abstract: To evaluate the prognostic significance of various clinicopathologic parameters and the implication of the National Institutes of Health ( NIH ) grading criteria for gastrointestinal stromal tumors ( GISTs ). Methods: A total of 124 GISTs with complete clinicopathologic data were retrieved from the archived files of the Department of Pathology, Affiliated Hospital of North Sichuan Medical College. The clinical features, site of occurrence, tumor diameter, and mitotic index were studied and statistically analyzed. The biological potential based on the newly edited NIH grading criteria was evaluated. Results: Of the 124 cases, 13 were advanced ( malignant ) GISTs and 111 were localized, primary GISTs. The mean age of patients was 57 years. Follow-up information was available in 82 cases, 9 of which were advanced GISTs and 73 were localized, primary GISTs. For these 73 cases, survival analyses were conducted, and the large tumor size ( P = 0.009 ) and high mitotic index ( P < 0.001 ) were associated with lower survival. Statistical analysis shows that, with the largest tumor diameter at 5.1 to 10.0 cm, the non-gastric GIST had a lower disease-free survival ( DFS ) rate than gastric GIST ( P = 0.011 ). The survival rate had no correlation with age and sex. As evaluated by the new NIH ( 2008 ) grading criteria, the overall and DSF rates of high-risk GISTs were lower than those of the very low-risk, low-risk, and intermediate-risk ( P < 0.05 ). On the other hand, the overall and DSF rates of the very low-risk, low-risk, and intermediate-risk GISTs were not statistically different. Conclusion: The risk criteria for assessing the natural course of primary GISTs proposed by the NIH ( 2008 ) were validated. The indication of the NIH classification in the pathological diagnosis of GIST is beneficial to GIST prognosis assessment and provides guidance on its clinical treatment.