Abstract: An insulin delivery device comprised of a compartment limited by a semipermeable, ionically charged membrane, containing the enzymes glucose oxidase and catalase, is disclosed. The enclosed enzymes provide a means for varying the permeabiity of the membrane to stored insulin deposited within the compartment according to the magnitude of glucose concentration outside the compartment, thus facilitating continuous, physiologically regulated delivery of insulin to tissues. This device may be applicable for intracorporeal or extracorporeal use.