14576 Background: Surveillance is an alternative to retroperitoneal lymph node dissection or adjuvant chemotherapy for stage I M or NS TGCT. It has been shown to be associated with a low mortality rate of about 1%, similar to that of the other therapeutic options. However, there are few reports of long-term results. The aim of this retrospective study was to investigate late relapses in this setting. Methods: Screening of the computerized database from 1984 to 2005 for patients (pts) treated for a relapse of a M or NS TGCT at 10 years or more after an orchidectomy. Results: From 1994 to 2006, the files of 5 pts were retrieved. Two pts were referred from other institutions whereas 3 pts had initially been included in the surveillance program of the Institution out of a total of 88 from 1984 to 1996. (3.4% CI 95% 0.7–9.6). Initial histology was available in 4pts: it was pure mature and immature teratoma in one pt and mixed GCT with seminoma in 3 pts. There was no vascular invasion in any of the tumors. Relapse occurred between 10 and 13 years after orchidectomy (median 11 years). The diagnosis of relapse was made based on a systematic 10-year follow-up CT scan in one pt. The 4 other pts who relapsed presented with symptoms: abdominal and back pain due to retroperitoneal involvement in 2 pts, walking disability due to a spinal cord compression in one pt and acute respiratory distress syndrome due to massive metastatic lung involvement in one pt respectively. All 4 pts had bulky retroperitoneal masses. According to the IGCCCG classification, the prognosis was poor in 2 pts and intermediate in 2pts. One pt died of disease despite cisplatin-based chemotherapy. Conclusion: These data demonstrate that there is a small but clinically significant risk of late relapse of stage I M or NS GCT after orchidectomy alone and support the need for long-term surveillance and patient information. No significant financial relationships to disclose.