Phenylboronic acids are known to form covalent complexes with polyol compounds such as glucose. A novel polyelectrolyte, containing phenylboronic acid as a glucose-sensitive moiety, has been synthesized and used for the fabrication of glucose-sensitive hollow polyelectrolyte capsules using the layer-by-layer technique. The response to glucose was observed as a rather fast dissolution of the capsules when brought into contact with a glucose-containing medium. These polyelectrolyte capsules are the first polyelectrolyte capsules able to respond to a stimulus that can be provided by the human body ( i.e., an increase in glucose concentration). Therefore, the concept we present has promising applications in the biomedical field for the controlled delivery of insulin.