**1. Introduction**

Solid organ transplantation is the optimal treatment for selected patients with end-stage organ disorders. Two important immunologic barriers to SOT are HLA sensitization and ABO incompatibility. The options for transplant candidates with incompatible donors are prioritization to well-matched organs in the allocation system, such as acceptable mismatch and paired donation programs or desensitization. Experience from renal transplantation forms the basis of contemporary desensitization protocols in SOT. This chapter will discuss desensitization in HLA incompatible (HLAi) and ABO incompatible renal transplantation. A brief account of desensitization in cardiac and lung transplantation is also provided.
