A case of secondary chronic myelogenous leukemia after successful therapy for Hodgkin's disease is reported. The patient was diagnosed as having stage IIIA Hodgkin's disease, at the age of 33. He underwent staging laparosplenectomy and was treated with radiotherapy plus chemotherapy. Forty three months after the diagnosis of Hodgkin's disease, a Philadelphia-positive chronic myelogenous leukemia developed. It required periodic chemotherapy and each time a remission, lasting several months (up to 14 months), was obtained. The disease had an unusually prolonged clinical course, and the blast crisis, of lymphoid type, occurred only 17 years later.