The case of a young man with stage IV chemoresistant pure seminoma overexpressing KIT, who achieved complete remission (CR) after the administration of imatinib mesylate (400 mg once daily), along with a third-line chemotherapy regimen, consisting of paclitaxel (150 mg/m2), oxaliplatin (100 mg/m2) and gemcitabine (800 mg/m2) every 2 weeks with granulocyte colony-stimulating factor (G-CSF) support is reported. The patient had received first- and second-line regimens consisting of ifosfamide, bleomycin, etoposide cisplatin (5 cycles, every 3 weeks) and methotrexate, vinblastine, actinomycin D, cyclophosphamide, cisplatin (3 cycles, every 3 weeks) respectively, without having normalized beta-human chorionic gonadotrophin (beta-HCG) levels. Following treatment with imatinib plus third-line chemotherapy (paclitaxel, oxaliplatin, gemcitabine), the levels of beta-HCG were reduced to within the normal limits during the first month of treatment. Therefore, the patient underwent surgical resection of the residual disease from the retroperitoneum and liver, which proved to be only necrotic tissue. The patient is under close follow-up, with no evidence of disease, 36 months after the completion of chemotherapy and 32 months post surgery.