Cellular drug resistance is an important limiting factor in the success of chemotherapy in childhood acute myeloid leukemia (AML). We summarize the results of the studies published sofar that have focussed on drug resistance in childhood AML, using cell culture assays. We also briefly report our own results of an ongoing study. Finally, potential applications of cellular drug resistance testing are discussed. It appears that cellular drug resistance differs between AML and acute lymphoblastic leukemia and between subgroups of AML patients, that AML cells of relapsed patients are more resistant to cytarabine than those of untreated patients, and that in vitro resistance to cytarabine and daunorubicin is related to a worse prognosis. However, more and larger studies are required to determine the exact role of cellular drug resistance testing in the treatment of childhood AML.