Amperometric biosensors based on alcohol oxidase (AOX) immobilized on the conducting polymers of 3,4-ethylenedioxythiophene (PEDOT) and 4,7-dithien-2-yl-2,1,3-benzothiadiazole (TBTD) were constructed. Proposed biosensors were characterized using ethanol as the substrate and the responses were measured. Kinetic parameters, I-max, K-m and sensitivity were determined for the biosensors with or without TBTD. Optimization studies for TBTD thickness, PEDOT amount and pH were carried out. The biosensing capacity was discussed for TBTD matrix.