The cellular immune response was explored by us with the help of tuberculin and DNCB reactions in 73 cases of Hodgkin's disease. Serum immunoglobulins were simultaneously determined. Tuberculin and DNCB reactions had significantly been decreased before treatment. A significant augmentation of the IgA is remarkable in tuberculin and DNCB positive groups. The positivity of the cutaneous tests is only temporarily lowered by radiation therapy, the difference being not significant, while IgM values in patients who had undergone radiation therapy are remaining at a lower level. Patients in remission revealed a positivity in tests that was approximating the values before treatment. Lower values were observed in all the three groups of immunoglobulins; the decrease of the IgM-values was significant. In case of a relapse, a significant decrease of positivity developed, accompanied by significantly increased values of IgA in tuberculin and DNCB negative groups. Only insignificantly positive values of the cutaneous tests were seen in the course of cytostatic treatment, and the values of the IgM were significantly decreased.