Makroglobulinemia Waldenstrom (Waldenstrom macroglobulinemia, WM) adalah varian plasmacytoid lymphocytic lymphoma yang memproduksi Ig M monoklonal dalam jumlah besar, menimbulkan makroglobulinemia yang mengakibatkan hiperviskositas dan volume plasma meningkat. WM merupakan kasus jarang, biasanya ditemukan pada pria umur pertengahan dan lebih tua. Diagnosis ditegakkan bila dijumpai gejala klinik, Ig M serum >1,5 g/dL, sumsum tulang: infiltrasi limfosit, sel plasma dan limfosit plasmasitoid, laju endap darah meningkat, histologi kelenjar getah bening gambaran sel limfoplasmasitoid. Dilaporkan kasus, laki-laki, 43 tahun dengan keluhan muka pucat, mata kabur, nyeri kepala disertai riwayat epistaksis, gusi berdarah dan melena berulang. Pemeriksaan fisik anemis. Pemeriksaan laboratorium didapati pansitopenia, morfologi darah tepi normokrom normositer, LED 115 mm/jam, Ig M serum 9,6 gr/dL. SPE menunjukkan M-spike. Dari BMP dijumpai hiposeluler, limfosit 61,25%, sel plasma (sel limfoplasmasitoid) 6,5% kesan WM. Hasil gastroskopi kesan ulkus akut di korpus dan gastritis erosif di antrum. Pasien didiagnosis WM dan diberi terapi suportif yang menghasilkan perbaikan klinis. Pasien direncanakan mendapat kemoterapi CHOP (siklofosfamid, doksorubisin, vinkristin, prednison).Waldenstrom Macroglobulinemia (WM) is a variant of plasmacytoid lymphocytic lymphoma producing monoclonal Ig M in large quantity, causing macroglobulinemia resulted in hyperviscosity and increased plasma volume. WM is rare, usually found in middle aged men and older. Diagnosis is confirmed with appropriate clinical symptoms, serum Ig M >1.5 g/dL, bone marrow lymphocytes infiltration, plasma cells and plasmacytoid lymphocytes, increased erythrocyte sedimentation rate, lymphoplasmacytoid cells in lymph node. This is a report of a 43 year-old male with complaints of pallor, blurred eyes, headaches accompanied by a history of epistaxis, gum bleeding and recurrent melena. Physical examination reveals anemia. Laboratory tests found pancytopenia, normochromic normocyte, ESR 115 mm/h, serum IgM 9.6 g/dL. SPE showed M-spike. BMP encountered hypocellularity, 61.25% lymphocytes, plasma cells (cells lymphoplasmasitoid) 6.5%. Gastroscopy suggests acute ulcer in the corpus and erosive gastritis in the antrum. Patients diagnosed as WM and given supportive therapy resulting clinical improvement. Patients were scheduled to receive CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisone).