In order to find out the potential indicators predicting prognosis of malignant gastrointestinal stromal tumors (GISTs) after surgical resection,we collected clinical records of 80 patients with malignant GISTs.Tumor location,size,mitotic index,necrosis were compared with the prognosis of malignant GISTs by Kaplan-Meier method and log-rank test.After a median follow-up of 844 days (52-2 145),we found that as National Institutes of Health suggested,tumors with intermediate risk had more favorable prognosis than that with high risk.Their 3-year survival rate were 65.3％ and 41.3％,respectively (P ＜ 0.001).Moreover,tumor size and mitotic index were associated with free survival.The 3-year survival rate for patients with tumor size ≤ 10 cm and ＞ 10 cm were 62.3％ and 41.8％,respectively (P =0.002),Tumors with mitotic index ≤ 5/50 HPF had a higher 3-year survival rate than tumors with mitotic index ＞ 5/50 HPF (67.1％ versus 40.7％,P =0.005).The presence of necrosis was directly related to the malignant behavior.The 3-year survival rate for presence and absence necrosis were 50.8％ and 64.8％ (P =0.008).From the present study,we can conclude that besides tumors size and mitotic index,tumor location and necrosis also influence on the long-term survival of patient with malignant GISTs after surgical resection.