Auto-SCT is the standard first-line consolidative therapy in patients with multiple myeloma (MM). We performed a national benchmarking outcome analysis for patients with MM who underwent a single auto-SCT in 1999 and 2005. They were identified from the British Society of Blood and Marrow Transplantation (BSBMT) (n=211 and n=453) and EBMT (n=1311 and n=1978) registries. An improvement in Day+100 and D+365 non-relapsed mortality (NRM) was shown between years 1999 and 2005 (P=0.0495). The 4-year relapse rate (RR) was significantly higher in 2005 (P=0.0003) and was associated with a shorter time to next treatment (TTNT) (P=0.025). The 4-year PFS was significantly lower in 2005 (P=0.0012), with the year of auto-SCT (P=0.001) and status at auto-SCT (P=0.02) being independently significant. The 4-year OS was similar between the year cohorts (P=0.266). In the 'benchmarking' comparison, the European Group for Blood and Marrow Transplantation (EBMT) 1999 cohort demonstrated the best PFS, although no year-of-transplant effect could be demonstrated on the 4-year OS rates (P=0.760). An improvement in supportive care resulting in reduced NRM is evident between the decades. The main cause of treatment failure remains disease progression. The similarity in OS between the years may reflect the introduction of novel agents in salvage therapy. The reduced PFS in 2005 is as yet not fully explained, but may represent recent disease response criterion standardization.