Non-Hodgkin's lymphomas form a heterogeneous group of tumors whose incidence is rising in elderly subjects. While most cases are accessible to treatment with chemotherapy, elderly patients tolerate treatments less well than younger ones. Nevertheless, treatment efficacy does not seem different. Two approaches can thus be proposed: the first is to give the patient a conventional treatment with a higher risk of toxicity, the second one would be to propose a "lighter", dose-adapted treatment. Two examples are examined more closely: diffuse large B-cell lymphomas and follicular lymphomas.