An 8-year-old intact male Pug was referred to the Cornell University Hospital for Animals in July 2012 for further management of severe thrombocytopenia and anemia due to gastrointestinal bleeding. The patient was diagnosed with primary immune-mediated thrombocytopenia, and began a regimen of immuno-modulatory drugs including dexamethasone, mycophenolate, cyclosporine, and intravenous immunoglobulin (IVIG). The patient failed to respond to medical management, required numerous blood product transfusions, and a splenectomy was eventually performed. This case report will discuss the clinical presentation, diagnosis, medical and surgical treatments, and prognosis of canine immune-mediated thrombocytopenia