Testicular seminoma represents a modern model of a multidisciplinary approach to a curable neoplasm. Surgeons, radiation oncologists, and medical oncologists play an important role in disease detection, diagnosis, treatment, and follow-up. This article focuses on the management of men who have early-stage seminoma, which represents stage I and IIa (minimal retroperitoneal spread). In stage I disease, the major controversies continue to revolve around surveillance versus adjuvant treatment and more recently adjuvant radiotherapy or carboplatin-based chemotherapy. Focus on long-term complications, such as cardiovascular disease, gastrointestinal disease, and secondary cancers, has led to the concept of increased surveillance with therapy for those who relapse. Radiation therapy remains the mainstay of therapy for patients who have stage IIa disease.