Background: Surveillance is recommended for patients with stage I seminoma post orchidectomy but CT imaging involves ionising radiation, with risk of associated secondary malignancies. We assessed site of disease relapse during surveillance to guide development of a risk adapted imaging protocol. Methods: Data was obtained from a prospectively maintained database of patients with stage I seminoma on surveillance after orchidectomy from 1981-2011. Relapse was determined by clinical and/or radiographic finding with or without pathological confirmation or tumour marker elevation. Results: 753 patients were identified. The median age at orchidectomy was 33.7 years. With a median follow up of 10.5 years, range 1.1-30.1, 115 (15.3%) patients relapsed. Relapse was detected radiologically in 114 (99.1%), with 9 (7.8%) having simultaneously elevated tumour markers. A clinical diagnosis of relapse was made in 1 case (inguinal node – 0.9%). The location and time to relapse are shown in table. Conclusions: In stage I seminoma surveillance, pelvic nodal relapse was restricted to the early period of follow up. Excluding the pelvis during CT imaging after the third year of surveillance may optimise the detection of relapse whilst minimising total radiation exposure. This has now been adopted at our centre since 2011 without any subsequent late pelvic relapses.