Background: Waldenstrom macroglobulinemia (WM) is a rare, dormant hematologic disease. It often manifests in people over 60 years of age and considered a hereditary disorder with MYD88 and CXCR4 genes mutation. In Indonesia, WM medical records is limited, causing potential misdiagnose or mistreatment. This article reported a case of WM patient and its challenging diagnosis establishment. Case Presentation: A 67-year-old woman was referred with chief complaints of extremities swelling with recurrent anemia, bone pain, and elevated renal function. Protein electrophoresis indicated monoclonal gammopathy, suspected as multiple myeloma. However, further examinations did not support the diagnosis of multiple myeloma as the results revealed increased B2 microglobulin (5.65mg/L). IgM immunofixation suggested IgM lambda monoclonal gammopathy. Bone marrow aspiration (BMA) showed dominant lymphoplasmacytic cells (68%) and flowcytometry test of serum plasma indicated positive CD10 and CD34, whereas CD5 and CD19 were negative. The differential diagnoses have also been ruled out one by one to provide appropriate treatment for the patient. After all examinations, the patient was finally diagnosed with WM and treated with bortezomib, low-dose dexamethasone, and rituximab (BDR) regimen for five cycles. Conclusion: WM is rare case of hematologic disease and the diagnosis of the case could face challenges due to diagnostic difficulty. Protein electrophoresis and BMA could help to improve the diagnosis process.