Backgraund. Primary amyloidosis belongs to a group of monoclonal plasma cell disorders, characterized by extracellular deposition of immunoglobulin light chain fibrils in various tissues and subsequent multiorgan dysfunction. Case report. We present a 51-year-old female with 2-years history of fatigue on exertion, oedema of face, abdomen and legs, bone pain and obstipation. After diagnostic procedures such as electrophoresis and immunoelectrophoresis of serum and urine proteins, immunohistohemical staining of bone marrow biopsy specimens and Congo red staining of rectal biopsy specimens, the patient received misdiagnosis of multiple myeloma and was referred to our hospital for further treatment. We reevaluated and complemented diagnostic procedures (ehocardiosonography and biopsy of subcutaneaus tissue with Congo red staining), and established diagnosis of primary amyloidosis. The therapy had started with intravenous (iv) melphalan and dexamethasone (totally eight cycles) and continued with peroral melphalan and iv dexamethasone. Stabilization of the disease was achieved after 35 months of the treatment. Conclusion. The case of this rare and often fatal disease emphasizes significance of early diagnosis and, consequently, initiation of specific therapies which are indispensable to improve the disease prognosis.