Two patients with alpha heavy chain disease are described. In the first patient, treatment with cyclophosphamide, prednisone and doxycycline was associated with a 28 month-long remission and the disappearance of the paraprotein and lymphoplasmocytic infiltration of the intestine. Shortly afterwards, a retroperitoneal immunoblastic lymphoma was found associated with an immunoglobulin G-kappa-paraproteinemia, and gamma heavy and kappa-light chains in the urine; the intestinal biopsy specimen was normal. In the other patient, the alpha chain only appeared two years after the malabsorption syndrome. The fact that in the first, apparently cured patient, a tumor of different anatomic site and secretory capacity appeared, suggests the existence of a B-cell neoplasia of different clone from that which gave rise tothe original disease. In the second patient, it is probable that only the increase in the mass of neoplastic cells led to the detection of the protein abnormality, or alternatively the antigenic-oncogenic stimulus led to the abnormal secretion only after two years.