Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only truly effective curative treatment for refractory hematological malignancies. Unfortunately, relapse and transplant rejection continue to be of major concern. In order to enhance the effectiveness of the HSCT, various strategies have been explored to amplify the graft versus leukemia (GvL) effect. Cancer vaccines have emerged in recent years as a promising strategy for the immunotherapeutic treatment of cancer. Evidence shows that they are most likely to have the greatest effect in the setting of minimal residual disease and as adjuvant agents. With this in mind, researchers have begun to explore the use of cancer vaccines in conjunction with HSCT, with exciting results. There has also been recent work examining the effect of novel adjuvants or blockers of negative immune regulation to augment the effect of cancer vaccines in both the transplant and non-transplant settings. The addition of these agents may prove.