Therapeutic practices for multiple myeloma (MM) have evolved, such that novel-agent–based therapy and autologous peripheral blood stem cell transplantation (aPBSCT) is the current standard. Whether cause-specific mortality has changed with time remains unclear. We examined late cause-specific mortality among patients with MM receiving aPBSCT from 1989 to 2014. We conducted a prospective cohort study using participants enrolled in the enrolled in the Blood or Marrow Transplant Survivor Study. We created 3 eras to reflect changing MM therapy: <2000 (pre-thalidomide); 2000-2005 (thalidomide); 2006-2014 (lenalidomide). We used Kaplan-Meier techniques and Cox regression for examining all-cause mortality, and subdistribution hazards models for cause-specific mortality. In total, 1906 patients were followed up for a median of 9.2 years. Conditional on surviving 2 years, the 10-year overall survival was 45%. The 10-year cumulative incidence of myeloma- and non-myeloma-related mortality was 33% and 13%, respectively. Multivariable analysis showed declining MM-specific mortality (subdistribution hazard ratio [SHR]2000-2005 = 0.80, 95% confidence interval [CI], 0.60-1.07; SHR2006-2014 = 0.46, 95% CI, 0.34-0.62; referent group: <2000), infection-related mortality (SHR2000-2005 = 0.50, 95% CI, 0.29-0.85; SHR2006-2014 = 0.35, 95%CI 0.21-0.60; referent group: <2000) and cardiovascular disease-related mortality (SHR2000-2005 = 0.45, 95% CI 0.20-0.99; SHR2006-2014 = 0.41, 95% CI 0.18-0.93; referent group: <2000). Although primary disease remains the major cause of late mortality, we observed a significant temporal decline in myeloma-, infection-, and cardiac-related late mortality over the past 25 years.