A feasibility study on high-dose therapy with autologous peripheral blood stem cell transplantation (HDT/PBSCT) was performed in Japanese patients with multiple myeloma (MM). Twenty evaluable patients younger than 65 years old with stage II/III MM were enrolled in this study. Three courses of VAD were used as initial chemotherapy. High-dose etoposide or cyclophosphamide followed by G-CSF was used for PBSCH, and 1.2-89.3 (median 23.4) x 106/kg of CD34+ cells were collected. Single (11 patients) or tandem (9 patients) HDT with melphalan (MEL) 200 mg/m2 or MEL 140 mg/m2 plus TBI 10 Gy were performed. The incidence of grade 4 toxicity (COG) was 10% and treatment-related mortality was 5%. Complete response and tumor reduction of more than 75% were obtained in 4 (21%) and 16 (84%) out of 19 patients, respectively. The actuarial 3-year overall survival (OS) and event-free survival (EFS) after PBSCT/HDT were 65.6% and 22.0%, respectively. The median EFS duration was 18 months. These preliminary results indicated that HDT/PBSCT is feasible for Japanese MM patients. A prospective randomized clinical trial will be required to assess the efficacy.