The effect of surface modification of Indium tin oxide by a NH2+ ion implantation technique has been studied to detect daunorubicin, an anticancer drug. The current was linearly dependent on the scan rate, indicating that the direct electrochemistry of daunorubicin in that case was a surface-controlled electrode process. The NH2/ITO electrode successfully detected the reduction signals of daunorubicin in the linear range of 1.0 x 10(-9)similar to 3.0 x 10(-6) M and the detection limit was 2.0 x 10(-10) M (at S/N = 3). NH2/ITO electrode exhibited high sensitivity, selectivity and good stability, and would be valuable for clinical assay of daunorubicin. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.030301jes] All rights reserved.