Abstract: The drug sensityivty assay in vitro of leukemic cells from 19 patients with acute leukemia for antileukemic drugs was investigated by the detecting technique of the amount of the argyrophilic proteins associated with nucleolar organiger regions (AgNOR). Application of chemotherapy drugs in the patients refered to the results of drug sensitivity assay in vitro. The results suggested the total corresponding rate of the drug sensitivity in vitro and the clinical chemotherapy response was 81.8%, the positive corresponding rate was 79.2%, the negative corresponding rate was 80.7%, the sensitivity and specificity were 95% and 61.5 %, respectively.The clinical therapy responses in acute non-lymphocylic leukemia were better than those in acute lymphocytic leukemia, complete remission rates were 84.6% and 33.3%, respectively. In conclusion, the AgNORs assay was simple, rapid and sensitive. The method has important value for chemotherapy of acute leukemia.