A new biosensor able to determine the hydrogen peroxide in water-saturated or anhydrous chloroform, operating directly dipped in non-aqueous solutions was prepared and characterized. The biosensor was obtained using an amperometric gas diffusion electrode for oxygen and modifying its response by means of physically immobilized catalase enzyme, which was superimposed on the teflon cap of the indicating electrode. Three different methods were used to immobilize the enzyme. The results obtained in a series of experimental tests, carried out in water saturated chloroform, using three different immobilization methods were compared and discussed on the basis of the response time, lifetime, sensitivity, useful range and main analytical data.Un noveau biocapteur capable de determiner le peroxide d'hydrogene dans l'eau saturee ou dans le chloroforme anhydre, et pouvant etre immerge directement dans des solutions non aqueuses a ete prepare: ce biocapteur a ete obtenu a partir d'une electrode amperometrique a diffusion de gaz pour l'oxygene, dont la reponse a ete modifiee au moyen de l'enzyme catalase, physiquement immobilisee et posee sur le bouchon en teflon de l'electrode indicateur. Trois methodes differentes ont ete utilisees pour immobiliser l'enzyme. Les resultats obtenus pour une serie d'experiences conduites avec du chloroforme sature d'eau, utilisant les trois methodes differentes d'immobilisation, ont ete compares et discutes sur la base des temps de reponse, sensibilite, intervalle utile et principales donnees analytiques.