From 1972 to 2001 at St. Bartholomew's Hospital 40 untreated Waldenstrom's macroglobulinemia (WM) patients received either chlorambucil (n = 23); cyclophosphamide, vincristine, and prednisolone (CVP) (n = 5); fludarabine-based therapy (n = 5); or other combination chemotherapy (n = 7). Twenty-eight patients (70%) responded to first-line therapy with overall response rates as follows: chlorambucil, 17/23 (74%); CVP, 4/5 (80%); fludarabine-based regimen, 2/5 (40%); other combinations, 5/7 (71%). Twenty patients were treated at progression with chlorambucil, of whom 10 (50%) responded again, 6/13 having had chlorambucil initially, and 4/7 having had other therapy. Although there was a trend towards a survival advantage for patients who responded to chlorambucil, this difference was not statistically significant. At 6 and 11 years, overall survival was 36% v 18% and 15% v 0% for responders and nonresponders, respectively. The overall pattern was the same for patients treated initially with chlorambucil as with other therapy. This retrospective analysis confirms that chlorambucil is an effective first-line agent in WM and has activity when used at subsequent relapse.