This study was performed to investigate the effects of dexamethasone on acute myelocytic leukemia (AML) cells. The study has been designed to investigate the in vitro effects of dexamethasone on the proliferative capacity, maturation and apoptosis of leukemic cells derived from patients with AML. Dexamethasone induced leukemic cell apoptosis and decreased cell count compared to the control. The percentage of cellular maturation increased in the dexamethasone groups compared to the control groups. Proliferative capacity of the cells was similar in all groups. These effects of dexamethasone on leukemic cells may be related to activation of the genes which stimulate apoptosis and maturation. More comprehensive studies are needed to evaluate the apoptotic effect of dexamethasone on AML cells.