Miniaturisation of the bedside artificial endocrine pancreas in necessary to provide a means of restoring physiological glycaemic excursions in diabetic patients in the long term. One of the remaining problems in producing such a sophisticated device is the difficulty in developing a sufficiently small glucose-monitoring system. A needle-type glucose sensor has been developed which is suitable for use in a closed-loop glycaemic control system. The wearable artificial endocrine pancreas, incorporating the needle-type glucose sensor, a computer calculating infusion rates of insulin, glucagon, or both, and infusion pumps, was tested in pancreatectomised dogs: the device produced perfect control of blood glucose for up to 7 days.