In this work, a new design of voltanunetric glucose biosensor, based on the encapsulation of glucose oxidase (GOx) in a chitosan/kappa-carrageenan (CHIT/CAR) polyelectrolyte complex (PEC) using a simple coacervation process is presented. A conductometric monitoring of this is performed. Spectroscopic and morphological characterization of the PEC film encapsulating GOx is carried out. Compared to biosensors based on a chitosan film, a more sensitive voltammetric detection of glucose is obtained. Using square wave voltammetry (SWV), the CHIT/CAR PEC based biosensor exhibits a wide linearity range from 5 mu M to 7 mM glucose with a detection limit of 5 mu M. Excellent selectivity against ascorbic acid, uric acid and urea is observed and the applicability of the biosensor for glucose detection in spiked saliva samples was demonstrated.