In some cases, long-term tumor-free survival might be possible for untreated primary diffuse large B-cell lymphoma (DLBCL) of the tonsil. Here, we report of 9 untreated patients who had primary tonsil DLBCL with long-term tumor-free survival. All these patients were children or young adults (4 male and 5 female individuals; ages: 6 to 38 y, median age: 25 y) with clinically evident swollen tonsils or papillary neoplasms. Tonsillectomy and biopsies indicated partial structural destruction of the tonsils with diffuse infiltration of large lymphoid cells. The large cells expressed CD20 with a Ki-67 proliferative index >50%. All samples were negative for CD5, Epstein-Barr virus-encoded RNA, and t(14;18) translocation. Except for cases 2 and 4, all samples showed monoclonal immunoglobulin gene rearrangements. Although chemotherapy and radiotherapy had not been administered after tonsillectomy (for various reasons), periodic imaging and clinical evaluation showed that none of the 9 patients developed or died of lymphoma (median follow-up: 40 mo). In conclusion, primary tonsil DLBCL does not always behave in a malignant manner, and some patients can achieve long-term tumor-free survival without chemotherapy or radiotherapy. On the basis of this case series, we concluded that close follow-up and observation might be possible for pediatric and young-adult patients who have undergone complete tonsillectomy for primary tonsil DLBCL with the following features: short disease course, morphologically early lesions, negativity for Epstein-Barr virus-encoded RNA and t(14;18) translocation, and no involvement of any other sites, after careful clinical evaluation.