OBJECTIVES: I. Determine the toxicity of rituximab or interferon alfa-2b maintenance therapy in patients with chronic lymphocytic leukemia or multiple myeloma in remission after chemotherapy. II. Determine the progression free survival, failure free survival, and overall survival of these patients from time of chemotherapy discontinuation to completion of maintenance therapy. III. Compare the survival rates of these patients to similar patients treated in published studies. IV. Determine the quality of life of these patients on these regimens.