From 1977 to 1989, we measured serum beta-2-microglobulin (beta 2-MG) levels from 64 unselected and untreated patients, between 18 to 50-year-old, affected by Hodgkin's disease. Serum beta 2-MG level was measured by radioimmunoassay (Phadebas beta 2 microtest). Then, all patients received a chemotherapy such as MOPP or alternating MOPP/ABVD followed or not by radiotherapy. Elevated serum beta 2-MG level (> 2.4 mg/l) is associated with advanced stage disease (stage III-IV), presence of systemic symptoms and bulky tumor. Nevertheless, a multivariate analysis shows that the serum beta 2-MG level is the most significant prognostic indicator for disease free survival. The prognostic value of serum beta 2-MG is demonstrated for myeloma and non Hodgkin's lymphoma. A few authors have evaluated the prognostic impact of serum beta 2-MG in Hodgkin's disease. This study requires confirmation by multicentric and prospective trial.