Twenty patients (median age 57 years) with high tumor mass myeloma in first remission after conventional chemotherapy received a two-phase treatment: autologous bone marrow transplantation (ABMT) using a preparative regimen of high dose melphalan plus total body irradiation followed by maintenance treatment with recombinant alpha interferon. Before ABMT all patients were in partial remission, while after ABMT 10 (50%) achieved complete remission, and 10 remained in partial remission (with a 90% decrease in measurable paraprotein in 7/10). With a median follow-up of 19.8 months (12.2-33.5) after diagnosis and 13 months (4-25) after ABMT, the Kaplan-Meier 2-year post-ABMT probability of progression-free survival was 85% (95% CI = 58.7-95.8%). None of the 10 patients in complete remission has relapsed. No toxic death occurred. Alpha interferon was introduced early after ABMT (2.7 months) and was well tolerated. This strategy may represent an advance in the management of aggressive myeloma.