The serum of a patient with a clinically and immunologically identified multiple myeloma of the IgE class was found to contain both IgE-albumin and IgG-albumin complexes. These complexes were partially purified and some of their properties studied by biochemical and immunoehemical methods. The IgG-albumin interaction was dissociated by 5.0 M guanidine hydrochloride, while the IgE-albumin interaction was dissociated upon reduction by mercaptoethanol, suggesting that the proteins were linked by intermolecular disulfide bonds. Complex formation between pathological or normal immunoglobulins with albumin have been reported for IgG, IgM and IgA but not for IgD or IgE. The present observation seems to be the first in which an IgE myeloma protein was involved.