One hundred and twenty-two patients with multiple myeloma were classified as mature, intermediate, immature, or plasmablastic subtype according to Greipp’s criteria. Contrary to Greipp’s report, the survival time of plasmablastic myeloma was not significantly shorter than other subtypes, nor was the plasmablastic subtype identified as a poor prognostic factor. The survival time of mature plus intermediate myeloma was significantly longer than that of immature plus plasmablastic myeloma. Between the former and latter, significant differences were found for sex, clinical stage, thrombocytopenia, bone marrow plasmacytosis, renal insufficiency, bone destruction, and response rate to treatment. Therefore, it was suspected that the immature and plasmablastic subtypes were unfavorable prognostic factors in patients with multiple myeloma.