Two cases of malignant lymphoma of the ovary observed at the Division of Medical Oncology of the II Medical School of Naples, are described. One patient had a diffuse immunoblastic lymphoma confined to the ovaries, after accurate clinical-pathological staging. She received aggressive chemotherapy after surgery, and is disease free over one year after diagnosis. The second patient had a low grade lymphoma of the ovary that had spread throughout the abdomen. This patient failed to respond to first line chemotherapy. The literature on ovarian involvement by lymphoma is also reviewed, and prognosis according to different stages of the disease is explained.