['When unselected healthy adults in the community have their serum screened by cellulose acetate or paper electrophoresis, monoclonal gammopathy of undetermined significance (MGUS) may be found in 0.5-1%.', 'To report upon a 31 year follow up of MGUS in a New Zealand community.', 'Serum from 2,192 subjects (82% of the adult population) of a New Zealand town was collected in 1967 and subsequently screened by cellulose acetate electrophoresis. Eleven of the 2,192 (0.5%) were found to have MGUS. Clinical correlation was sought in 1970 and subsequently to elucidate the underlying cause.', "Seven of the 11 patients have developed a haematological malignancy. Two have been diagnosed as having Waldenstrom's macroglobulinaemia, one malignant lymphoma and acute myelomonocytic leukaemia and four developed myeloma. Myeloma developed at one, nine, 23 and 25 years after the original screening. One myeloma patient and one patient with MGUS are currently alive and well, 31 years after discovery of their gammopathy."] Do monoclonal gammopathy of undetermined significance ( MGUS ) -31 year follow up of a community study?