Clinical features, response to treatment and prognosis of 50 cases of immunoblastic lymph-adenopathy are reviewed. Most of the patients presented with generalized lymphadenopathy, hepatomegaly and/or splenomegaly, and fever. Hyperergic reactions such as pruritus, skin rash or eosinophilia were frequent. Erythrocytic sedimentation rate was increased by differing amounts. In some cases there was a polyclonal increase in immunoglobulins, while in others there was a reduction. Proven hypersensitivity to a wide spectrum of drugs was present in nine cases. Prognosis is uncertain: almost half of the patients died within one to forty-two months, some perhaps as a result of massive chemotherapy and/or radiotherapy. Best management probably is symptomatic treatment alone or with small doses of corticoids or immunosuppressives, supplemented by antibiotics. It is concluded that immunoblastic lymphadenopathy represents a hyperimmune reaction and is not, despite the high death-rate, a true malignant lymphoma.