Radical surgery is the primary treatment for gastrointestinal stromal tumor (GIST), so that unrsectable GIST has been considered a fatal disease, and the median duration of survival for patients with an unresectable GIST before the era of molecular targeted therapy has been about 18 months. Since the recent development of agents for molecular targeted therapy, including imatinib mesylate, the prognosis of unrsectable GIST has been dramatically improved. The B2222 trial reported that a median time to progression and a median overall survival for advanced GIST treated with imatinib of 24 months and 57 months, respectively. We recently experienced a case of gastrointestinal stromal tumor with synchronous liver metastases maintained in whom the disease was controlled for 4 years by imatinib. The patient is 37-year-old man and he took imatinib mesylate at 400mg/day with no adverse events. Both primary and metastases lesions responded well to imatinib treatment, and this efficacy has endured for 4 years, such that surgical intervention is now considered possible. While GIST is a relatively rare disease and clinical evidence is still poor, we document our considerations for the therapy in this case as well as the results.