Development of new biosensors has extremely importance in medicine. The main targets are the miniaturization of these devices, less invasive methods to the patient, high sensitivity and fast response. The deposition method to produce the oxide thin films has great influence on films properties, to be used as sensitivity layer of a biosensor. Several oxide materials have been developed to find the higher sensitivity, close to Nernst equation and fast response. Titanium oxide, fluorine-doped tin oxide and indium tin oxide are compared using different deposition techniques. The higher sensitivity was reached using fluorine-doped tin oxide prepared by chemical vapor deposition (about 58 mV/pH).