Acute kidney allograft rejection is the major cause for a loss of graft function and has a negative impact on long-term graft survival. Anti-rejection therapy traditionally focuses on T cell-mediated mechanisms of renal allograft rejection. However, available agents that affect T-cell pathways have only little impact on long-term graft survival. There is increasing evidence that B-cells play an important role in acute transplant rejections. CD20+ B cell infiltrates in acute T-cell mediated rejections are frequent and correlate with a worse response to conventional anti-rejection treatment and an increased risk of graft loss. In one pilot study, supported by several case reports, a beneficial effect of Rituximab for the treatment of acute rejection episodes with intrarenal B-cell infiltrates was shown. However, despite the promise of these observations solid evidence is required before incorporating this treatment option into a general treatment recommendation.