Abstract: Objective: To explore the CT and MRI characteristics of testicular seminoma, in order to improve the understanding of the disease. Methods: The CT and MRI features of 13 cases of surgically and pathologically confirmed testicular seminoma were reviewed retrospectively. Results: Three of the 13 cases were seminoma of undescended testes. The CT scans of testicular seminoma showed relatively homogeneous density and mild-moderate enhancement. MR imaging showed intratesticular lesion which was nodular and of slight hyposignal intensity on T2-weighted images, with hypo-intensity fibrovascular septa enhanced more obviously than tumor tissue. Seminomas of undescended testes were located along the path of testicular descent. The tumor was ectopic to pelvic cavity and retroperitoneum, lesion volume was larger. They were of heterogeneous density or signal intensity with marked enhancement on post-contrast scan. Conclusion: The CT and MRI features of testicular seminoma are characteristic for the diagnosis and differential diagnosis of the tumor.