Non-Hodgkin's lymphomas (NHL) involving the uterus may be either low-stage neoplasms that probably arise in the uterus (primary) or systemic neoplasms with secondary involvement. In this study, 26 NHL involving the uterus are reported. Ten cases were stage I(E) or II(E) and are presumed to be primary. The mean age of patients at presentation was 55 years (range, 35 to 67 years), and abnormal uterine bleeding was the most frequent complaint (six patients). Nine of 10 tumors involved the cervix. Histologically, eight were diffuse large B-cell lymphoma (DLBCL); one was follicle center lymphoma, follicular, grade 1; and one was marginal zone B-cell lymphoma. At 5 years of clinical follow-up, five of six patients were alive after treatment. In 12 cases, uterine involvement was part of a systemic disease at diagnosis, either stage III(E) or IV. The mean patient age at the time that uterine involvement was detected was 58 years (range, 22 to 75 years); 6 of 12 had abnormal uterine bleeding. Six tumors involved both cervix and corpus, four corpus, and two cervix. Six were DLBCL; two were small lymphocytic lymphoma; three were follicle center lymphoma, follicular, grade 1 (two cases) or grade 2 (one case); and one was precursor T-cell lymphoblastic lymphoma. At 5 years of clinical follow-up, two of seven patients were alive after treatment. Four DLBCL arose in patients with incomplete clinical information; therefore, stage is unknown. We conclude that low-stage (presumably primary) uterine NHL are most commonly DLBCL, predominantly arise in the cervix, and cause abnormal uterine bleeding. High-stage NHL are a heterogeneous group of B-cell neoplasms that can involve the cervix or the corpus.