Waldenström's or primary macroglobulinaemia has rarely been documented in Black Africans. Six South African Negro patients with Waldenströms macroglobulinaemia were assessed and followed during a 10-year period from 1966 to 1976. The hyperviscosity syndrome was the presenting feature in four patients and one patient each presented with the nephrotic syndrome and a lacrimal mass respectively. On initial evaluation of the six patients, the serum IgM varied from 1.3 to 4.8 g% and in two patients cryoglobulinaemia was found. The patients received supportive treatment, chemotherapy, and when necessary, plasmaphoresis. One patient was lost to follow-up, one patient died 7 years after the onset of his illness, but the remaining four patients are alive 18 months to 5 years after presenting with their disease. Although the disease occurred in a younger age group (mean age 43 years) than in Caucasians it did not differ in clinical features or response to treatment from other parts of the world.