Introduction: In this study, the effect of age on the prognosis of testicular germ cell tumors in patients over 40 was investigated. Materials and Methods: Ninety- three patients with testicular germ cell tumor who were 40 years old and over were identified in our germ cell tumor database. Patients were grouped according to their age with those between 40 and 44, 45 and 49 and 50 and over constituting groups I, II and III, respectively. Results: Only 15% of the patients of group III had localized disease ( p = 0.002). Group III patients had a significantly lower response rate to initial chemotherapy and a higher disease progression rate during therapy ( complete response rate: 33.3%, progression rate: 44.4%, p = 0.035). The multivariate analysis revealed that advanced stage was the only independent prognostic factor for survival ( p = 0.0011). Conclusion: Testicular germ cell tumor patients over 50 years old presented with a more advanced stage and had higher disease progression and disease mortality rates.