To compare the clinical outcomes of older (age > or =55 years) non-Hodgkin lymphoma (NHL) patients with younger NHL patients (<55 years) receiving autologous hematopoietic cell transplantation (HCT) while adjusting for patient-, disease-, and treatment-related variables, we compared autologous HCT outcomes in 805 NHL patients aged > or =55 years to 1949 NHL patients <55 years during the years 1990-2000 using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). In multivariate analysis, older patients with aggressive histologies were 1.86 times (95% confidence interval [CI] 1.43-2.43, P < .001) more likely than younger patients to experience treatment-related mortality (TRM). Relative death risks were 1.33 times (CI 1.04-1.71, P = .024) and 1.50 times (CI 1.33-16.9, P < .001) higher in older compared to younger patients with follicular grade I/II and aggressive histologies, respectively. Autologous HCT in older NHL patients is feasible, but most disease-related outcomes are statistically inferior to younger patients. Studies addressing supportive care particular to older patients, who are most likely to benefit from this approach, are recommended.