Transfusions of blood products are common in medical practice and can be lifesaving in certain situations. Potentially life threatening reactions could occur and physicians should be alerted. Here we describe a case of thrombocytopenia that was induced by transfusion of fresh frozen plasma (FFP). A 52 years old male presented to the emergency department after two episodes of hematochezia that resolved spontaneously. Since he was anticoagulated for atrial fibrillation he was given a unit of FFP to reverse a slightly elevated INR. Within 6 hours from the administration of the FFP he developed an acute decrease only in his platelet count. He was managed conservatively and his thrombocytopenia started resolving gradually. After excluding other causes the potential diagnosis was fresh frozen plasma induced thrombocytopenia. The pathophysiologic mechanism is postulated to be immune mediated by passive transfer of antibodyies from the donor to the recipient. The antibodies that are described in the literature are anti-HPA-1a and anti-CD-36. We reported the event to the American Red Cross. Interestingly a male was the donor of the plasma while in all cases in the literature the donors are females with a prior history of pregnancy. Therefore this is the first reported case of a male blood donor whose blood product caused immune mediated thrombocytopenia post transfusion.