Kaposi's sarcoma-associated herpesvirus (KSHV) is suspected to play a role in the aetiology of multiple myeloma. Because of similarities in the pathophysiology of multiple myeloma and Waldenstrom's macroglobulinaemia (WM), we investigated DNA samples from 20 bone marrow biopsies with WM for the detection of KSHV by PCR (KS330/ORF26). We performed two rounds of amplification and found that only 1/20 of the DNA samples obtained from biopsies had a detectable KSHV sequence. The positive patient was also infected by the human immunodeficiency virus (HIV). Our data provide evidence that KSHV cannot be implicated in the pathogenesis of WM.