Patients who have an inadequate increase in their platelet count following platelet transfusion are a common problem for the transfusion service. Only some of these patients are truly refractory to platelet transfusion and need additional testing. At the same time, repeated platelet transfusions to these refractory patients are an ineffective use of a scarce product. Furthermore, not every patient who is refractory to platelet transfusion will benefit from special products such as HLA-matched platelets. Proper identification and management of patients who are refractory to platelet transfusion can minimize unnecessary expenditures of time, products and money for the transfusion service. This program will discuss the criteria necessary to establish a diagnosis of platelet refractoriness and therapeutic approaches which maximize the quality of patient care while minimizing expenses to the transfusion medicine service.