Patients with myelodysplastic syndromes (MDS) show a decrease in the number and function of natural killer (NK) cells, including lymphokine activated killer (LAK) cell activity. Interleukin-2 (IL-2) stimulates the proliferation and activity of these lymphocytes. Anecdotal clinical experience has shown haematological and cytogenetic improvement in myelodysplasia by low-dose IL-2 treatment. A total of 10 patients with MDS were treated with 1 million units of IL-2 subcutaneously daily for 12 weeks. Even though improvement in CD16+/CD56+ cell numbers was seen in a majority of the patients, the haematological status and transfusion requirements remained unchanged. There was minimal toxicity from this therapy.