One hundred and thirty patients suffering from multiple myeloma were reviewed for retrospective study of their classification according to Durie and Salmon's staging system. No significant difference was found in survival between patients in stage I, II and III. Since then, each criterion developed by Durie and Salmon was evaluated separately. Only the Hb level showed a significant influence; a Hb level under 8.5 g/dl or corrected calcaemia above 3 mmol/l were never found separately. When survival according to the number of criteria was considered there was no difference. These findings agree with the well-founded classification of Durie and Salmon but the real importance of each criteria is questionable.