pH-ISFETs, the semiconductor pH sensors, were combined with immobilized enzyme membranes to prepare FET type urea and glucose sensors and its operational characteristics were investigated. Photolithography techniques wore applied to immobilize enzymes on the H^+ sensing membrane of the pH-ISFET with photo-sensitive polymers, PVA-SbQ. Fabricated urea and glucose sensors could determine 0.5∼50 mg/dl urea concentrations and 10∼1000 mg/dl glitdbse concentrations, respectively.