We compared the safety and efficacy of allogeneic stem cell transplantation (allo-SCT) after reduced-intensity conditioning using either unrelated umbilical cord blood (UCB) donors or matched-sibling donors (MSDs) for 21 adults at high risk with advanced Hodgkin lymphoma (UCB, n = 9; MSD, n = 12). Both groups were comparable except for younger age in the UCB cohort (median, 28 vs 42 years; P = .02). Neutrophil recovery occurred earlier in the MSD group (median, 7 vs 10 days; P = .02). All patients had sustained donor engraftment by day 60. Cumulative incidence of acute severe graft-versus-host-disease (33% vs 33%; P = .99), chronic graft-versus-host-disease (11% vs 33%; P = .24), and 100-day treatment-related mortality (11% vs 17%; P = .80) were comparable. With median follow-up periods of 17 and 24 months, the 2-year progression-free survival rates were 25% (95% confidence interval [95% CI], 0%-55%) for UCB and 20% (95% CI, 0%-44%) for MSD allo-SCT (P = .67). Our results suggest comparable outcomes for reduced-intensity allo-SCT using UCB or MSD in adults at high risk with advanced Hodgkin lymphoma.