OBJECTIVE We conducted an outcome and complications analysis of patients treated with adjuvant radiotherapy (RT) for early-stage testicular seminoma over a 35-year period at the University of Florida. METHODS All 73 patients had the classic seminoma histology. No patient received chemotherapy as initial treatment. There were 57, 14, and 2 patients with Royal Marsden stage I, IIA, and IIB disease, respectively. All received RT to the paraaortic (PAN) and pelvic fields. One-third of the patients received prophylactic RT to mediastinal/supraclavicular fields. RESULTS Median follow up was 15 years. Median RT dose to PAN and pelvic fields was 25 Gy. Local control and cause-specific survival at 20 years were 95% and 96%, respectively. Of the 3 recurrences, 1 was salvaged with chemotherapy. Subset analysis of 41 patients revealed 1 patient who developed peptic ulcer disease and 11 patients with gastrointestinal reflux symptoms after RT. Thirty-two patients fathered a child before or after RT. Cardiovascular complications were not greater in those treated with prophylactic RT to the mediastinal region. The rate of nontesticular second malignancy for the overall group was 8% at 15 years. CONCLUSIONS Patients treated with adjuvant low-dose RT to the paraaortic and pelvic fields for treatment of early-stage seminoma enjoy an excellent long-term cure rate with minimal risk of late RT complications.