Background: Gastrointestinal stromal tumors (GIST) are rare tumors of the gastrointestinal system. The most common primary site of GIST is the stomach. The treatment is primarily surgery, and the standard medical therapy is imatinib. Long-term survival can be obtained with good follow-up and treatment. Materials and Methods: In this study, data entry was performed using a webbased patient registry system for patients who were referred to 3 centers and retrospectively were diagnosed with GIST. Results: The study cohort consisted of 249 patients, including 160 men (64.3%) and 89 women (35.7%). The mean age was 59 years (range 21-90 years). Initially, 69.9% of the patients had local disease, while 30.1% had metastatic disease. The tumor was located in the stomach in 45.6% of patients. According to the Fletcher risk classification, the very low risk group included 8 subjects (3.2%), the low risk group included 40 subjects (16.1%), the moderate risk group included 56 subjects (22.5%), and the high risk group included 117 subjects (47%); the unspecified group included 28 subjects (11.5%). Conclusion: These data are important for revealing the clinicopathologic characteristics and survival data of patients with GIST, who are treated and followed up in Turkey.