The therapy of primary amyloidosis is still unsatisfactory. The response rate after cytostatics, dimethylsulphoxide, colchicin and vitamin E is usually low. None of these treatment modalities prolongs significantly the survival in the majority of treated patients. The success of interferon alpha in the maintenance therapy of follicular non-Hodgkin's lymphoma and in the remission of multiple myeloma, as well as successful treatment of primary cryoglobulinemia, brought us to the idea to test interferon alfa in the therapy of primary amyloidosis. Interferon alpha-2b was administered to a patient with three years history of primary amyloidosis. Interferon alpha was used in the dose of 3 x 10(6) i. V. daily for a treatment period of 10 weeks. The evaluation of the response was based on the weekly assessment of the light chain lambda concentration in the morning spot of urine. No significant decrease of the light chain concentration during the course of the therapy was observed. The administration of interferon alpha-2b was interrupted in the 10th week of the therapy because of manic psychosis. The question is, whether a higher dose than 3 x 10(6) IU daily would be able to decrease the light chain production, or if this disease is resistant to interferon alpha therapy. Because of the low incidence of primary amyloidosis, the experiences will be collected on the base of small groups of case reports.