SummaryThirty observations of paraproteins not including multiple myeloma or Waldenström’s macroglobulinemia, are reported. Certain diseases my be associated with this protein anomaly : hepatic, hematologic, tumoral and infectious diseases. Some paraproteinemias appear with advanced age in otherwise healthy individuals.The reversibility of such protein abnormalities with the control of the primary disease, and the demonstration of paraprotein immunologic reactions, constitute arguments for considering these paraproteins as isolated antibodies. These antibodies produced by an anarchistic cellular clone demonstrate specific activities which are not necessarily linked to the etiological agent of the disease.