Therapy of low-grade of malignancy non-Hodgkin's lymphoma in an advanced stage is still under discussion: aggressive poly-chemotherapies, such as radiotherapy and conventional chemotherapies did not prove to be more effective than conservative treatments. We report the case of a woman suffering from a low-grade of malignancy non-Hodgkin's lymphoma (stage IV-B). She was in such bad general conditions that she could not be treated with chemotherapy. She received an immunostimulating drug, thymopentin for 10 months. After this treatment, the general condition of the patient was improved and a partial remission of the lymphoproliferative disease was observed. The patient is still in constant fairly good health.