Multiple in vivo and in vitro immune parameters were used to examine 52 untreated patients with Hodgkin's disease in all stages. A significant number (p less than 0.01) of patients in all stages demonstrated abnormalities in DNCB sensitization, peripheral blood lymphocyte response to phytohemagglutination, absolute lymphocyte count, absolute number of T cells (as measured by spontaneous rosette formation with sheep erythrocytes), and absolute number of B cells (as measured by immunofluorescence with polyvalent antiserum). The number of T and B cells fell progressively with each stage, but the proportion of T to B cells remained constant. Cutaneous anergy was found in STAGES III and IV. Depressed circulating immunoglobulins were found in a few patients in all stages. Neither the total lymphocyte number nor the number of T and B cells correlated with the measures of lymphocyte function (skin test reactivity, DNCB sensitization, mitogen response, or immunoglobulin levels). This study suggests that selective abnormalities in the immune system exist even in early Hodgkin's disease, involving the absolute number of circulating T and B lymphocytes and T-lymphocyte function. The study fails, however, to define a consistent pattern of immune defects as characteristic of Hodgkin's Disease.