Cases of Waldenstrom's macroglobulinemia (WM) in two employees of a university academic department were investigated as part of a NIOSH health hazard evaluation of a suspected cancer cluster. Among 11 persons in the social sciences department of a university in the southeastern US who were diagnosed with various types of cancer between 1985 and 1990 were two cases of WM in men who had worked in the same building. The building had been occupied by various social science departments since 1955. Before 1955, it had been occupied by the biology department from 1937 to 1947 and by the geology department from 1947 to 1955. Searches of records provided by the university radiation safety office, dissertation and masters theses databases, and faculty presentations and publications found no evidence that radioactive materials had ever been used in the building. Medical records of the cases confirmed the diagnosis of WM. Both cases were young at the time of diagnosis, 44 and 47 years. They had first entered the building 21 and 20 years before diagnosis, respectively. Neither had a history of chemical or biological agent exposures similar to those seen in previous WM case reports. The authors conclude that the two cases of WM have several features in common: young age at diagnosis, work in the same building, and similar duration of time between first entering the building and diagnosis. A common causal agent for the two cases of WM, a rare disease usually seen in males over the age of 60, has not been identified.