Salivary immonoglobulins of patients with multiple myeloma, lymphoid leukaemia, agammaglobulinaemia and of normal healthy adults were examined. Higher IgG level was identified in 4 cases IgG monoclonal gammopathy. In these cases extremely large quantities of IgG monoclonal protein were transmitted from serum into salivary secretions. On the basis of the results it appears that monoclonal IgA is transferred to external secretions in patients with IgA monoclonal gammopathy. High IgM level was found in both serum and saliva of agammaglobulinaemic patients. "IgM secretory component" complex could be identified in saliva. In lymphoid leukaemic patients the salivary immunoglobulins presented normal values except of a patient whose tigA lacked in serum and also in saliva.