Multiple myeloma (MM) is a rare malignancy, characterized by clonal proliferation of plasma cells, secreting monoclonal immunoglobulin. It is usually diagnosed based on histopathologic and immunophenotypic bone marrow examination. Abnormal results of screening coagulation tests, including prothrombin time, activated partial thromboplastin time and thrombin time, are commonly encountered in patients with plasma cell neoplasms. They do not, however, reflect bleeding tendency. We describe a 71-year-old patient who was accidentally diagnosed with multiple myeloma during coagulation diagnostics.