Purpose: We performed a population-based study of primary testicular diffuse large B-cell lymphoma (DLBCL) in the United States to determine its incidence and survival trends, prognostic factors, and clinical outcome compared with males with nodal DLBCL. Patients and Methods: The Surveillance, Epidemiology, and End Results database was reviewed to identify patients diagnosed between 1980 and 2005. To study the potential impact of the introduction of rituximab on survival, we used the year 2000 as cutoff point. Results: We identified 769 patients with testicular DLBCL. The median age at diagnosis was 68.0 years. The incidence of DLBCL increased over time, with the highest rate among whites (twice that of blacks). The median overall survival (OS) for the whole group was 4.6 years, whereas the disease-specific survival (DSS) rates at 3, 5, and 15 years were 71.5%, 62.4%, and 43.0%, respectively. Independent predictors of worse DSS were older age, diagnosis before 1986, advanced stage, left testicular involvement, and not having surgery and radiation. The use of radiation did not change significantly over time. When testicular and nodal DLBCL patients were analyzed together, testicular primary was an independent predictor of better OS and DSS. Unlike nodal DLBCL, DSS did not improve in the patients with testicular DLBCL diagnosed after the year 2000. Conclusion: The incidence of testicular DLBCL is increasing. Compared with nodal DLBCL, testicular DLBCL patients have a better overall prognosis but are at higher risk of late disease-related deaths. The introduction of rituximab in clinical practice does not seem to improve their early outcome.