Purpose: To our knowledge there is no multi-institutional report on prepubertal testicular tumors in Korea to date. We obtained demographic data for a better understanding of the biological behavior and optimal management of these tumors. Materials and Methods: The prepubertal testicular tumor registry form was mailed to all 87 hospitals registered in the Korean Urology Association. We retrospectively reviewed recent 5-year medical records. Results: A total of 209 patients were enrolled in this registry. The incidence was 0.98/100,000 children. Age was I to 142 months (median 18). Most patients were diagnosed with a scrotal mass before age 4 years. Serum a-fetoprotein and P-human chorionic gonadotropin increased in as many as 62.9% and 2.7% of patients, including 94.7% and 2.2% in those with yolk sac tumor and 30.4% and 2.7% in those with teratoma, respectively. While potentially malignant tumors accounted for 52.5% of patients, the remainder were benign. Germ cell tumors were the most common (89.4% of cases), mainly with yolk sac tumor (47.8%) or teratoma (39.7%). Management after surgery included surveillance in 71.8% of cases, chemotherapy in 9.1%, combination therapy in 1.4% and other in 17.7%. Of the total patients 10.5% (5.9% of stage I yolk sac tumors) had progression to metastasis. The final results of treatment were complete remission (64.6% of cases), incomplete remission (2.9%), no response or disease progression (1.4%) and unknown (31.1%). Outcomes at the last followup (average 23.5 months) were 76.1% of patients alive, 0.9% dead and 23.0% of unknown status. Conclusions: Demographic data on pediatric testicular tumors in Korea will lead to a better understanding of these rare tumors and to optimal therapy in these children.