A 61-year-old woman presented with pancytopenia and underwent a bone marrow biopsy. The patient was diagnosed with nonsecretory myeloma (plasmablastic type) based on both the bone marrow biopsy findings and her laboratory data. Fluorine-18 fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) was performed prior to chemotherapy showing diffuse bone marrow uptake, splenic uptake, and focal uptake of the right anterior chest wall. The patient underwent an (18)F-FDG-PET examination to evaluate the curative effects after three cycles of chemotherapy, and no abnormal uptake on (18)F-FDG-PET was found. Bone marrow biopsy to evaluate the curative effect showed no viable tumor cells. We present a rare case of nonsecretory plasmablastic myeloma detected by (18)F-FDG-PET.