Prognostic factors in Hodgkin's disease (HD) are reviewed. The Ann Arbor staging classification remains the basis for evaluation of patients with HD. However, subgroups of patients with differing prognoses exist within the individual stages. In pathological stages I and II, the number of involved regions and the tumor mass in each region are important, and an estimate of the total tumor burden has proved significant. B symptoms, histological subtype, age, and gender are also generally significant but less important. Prognostic factors for laparotomy findings in clinical stages I and II are: number of involved regions, disease confined to upper cervical nodes, B symptoms, gender, histology, age, and mediastinal disease (variable influence). In clinical stages I and II, the same prognostic factors apply as for pathological stages I and II and for laparotomy findings, and also some indirect indicators of extent of disease such as erythrocyte sedimentation rate, anemia, and serum albumin. In advanced disease the number of involved nodal and extranodal regions, the total tumor burden, B symptoms, age, gender, histology, and a number of hematologic and biochemical indicators are significant. Research into serum values of certain HD-associated antigens and cytokines may in the future provide valuable tumor markers in HD.