We have treated 20 patients, affected by acute myelogenous leukemia in advanced phase of the disease, with intravenous high-dose recombinant interleukin-2 (IL2) as induction treatment, achieving a complete remission (CR) in 11/20 of patients (55%). All CR patients were planned to receive a maintenance program with lower subcutaneous doses of IL2 until relapse. Currently, 5/11 patients are alive in continuous complete remission with a minimum follow-up of 9 years from IL2 induction. In the aim to investigate the treatment's side-effects during or after prolonged IL2 therapy, we decided to submit these patients to a clinical and immunological evaluation. Four patients have been evaluated as one, who independently stopped IL2 after 6 years, refused the check-up. No organ-specific treatment sequelae that may decrease the quality of life or may be life-threatening were found, concerning renal, liver and cardiovascular function. Endocrine abnormalities were detected in three patients, the most serious being a severe hypothyroidism, which prompted cessation of IL2 maintenance after 6 years and required thyroid supplementation treatment. Immunological studies were carried out prior to the last IL2 cycle and showed high levels of CD3-positive T cells expressing the IL2 receptor alpha chain (CD25), both in the peripheral blood and in the bone marrow. Our study shows that low-dose IL2 can be given for a prolonged period of time without serious organ-specific late sequelae and with a good quality of life.