Auto-SCT is an effective therapy for patients with multiple myeloma (MM), but nearly a fifth of these patients relapse within a year of auto-SCT. We studied 494 patients, undergoing auto-SCT within 12 months of diagnosis of MM. Patients were divided into two groups: early relapse (relapse <or=12 months from auto-SCT) and late relapse (either relapsed >12 months after auto-SCT or disease free at the last follow up). One hundred twenty patients (24%) were in the early relapse and 374 (76%) were in the late-relapse groups. The early relapse group had a significantly shorter median overall survival (OS) from diagnosis (26.6 vs 90.7 months; P<0.001) and from auto-SCT (20.1 vs 82.5 months; P<0.001). Among the 345 patients who have relapsed after auto-SCT, median OS from relapse was 10.8 months in the early relapse group compared to 41.8 months for the rest (P<0.001) and was longer with increasing duration of response to the SCT. In multivariate analyses, labeling index >or=1% at transplant, greater than one treatment regimen prior to auto-SCT, and failure to achieve a complete response were predictive of early relapse. Patients who relapse within 12 months of an auto-SCT have a poor outcome and should be offered trials evaluating novel treatment approaches.