Brentuximab vendotin is a monoclonal antibody approved in August 2011 for use in patients with Hodgkin disease and a rare systemic lymphoma known as anaplastic large cell lymphoma. Brentuximab is approved in patients with Hodgkin disease who have failed autologous transplantation or after failure of at least two prior multi-agent chemotherapy regimens but has not been studied following allogeneic transplantation. Four patients with relapsed Hodgkin disease have been treated at our institution with at least two doses of brentuximab vendotin. Two patients have experienced significant infusion reactions on multiple occasions, and two patients have tolerated the infusions well. During phase 2 trials, there were no reports of Grade 3 or 4 infusion-related reactions. Both patients with reactions had relapsed following allogeneic stem cell transplants, while neither of the patients who tolerated the infusions had undergone transplantation. We report our experience with brentuximab vendotin-treated patients at our institution, focusing on the two post-allogeneic patients who experienced multiple significant infusion reactions. This report evaluates possible mechanisms behind their reactions, including previous allogeneic stem cell transplantation as a likely precipitating factor.