8-Hydroxydeoxyguanosine (oh8dG) treatment induced senescence-like changes in KG-1 cells, a human acute myelocytic leukemia cell line. The oh8dG-treated cells stained positive for senescence associated β-galactosidase (SA-β-galactosidase) and had enlarged cell shape, both of which are senescence indexes. The oh8dG-treated cells were also cell growth inhibited and arrested at G1 in the cell cycle. The accumulation of cdk (cyclin dependent kinase) inhibitors, such as p16, p21, and p27, also implies that cellular senescence was induced in oh8dG-treated cells. However, these changes were not accompanied by cell differentiation or telomerase activity. Taken together, we conclude that oh8dG treatment of KG-1 cells induces cellular senescence.