Because of their unique physicochemical properties, carbon nanotubes and graphene can find promising applications in many fields of biomedical research. However, the pristine nanomaterials suffer from low solubility in aqueous systems which results in their limited biocompatibility. Through the introduction of carbohydrates, the surface properties of these graphitic carbon nanostructures can be modified not just to improve their water solubility but also to enable these versatile nanostructures to interact selectively with biological systems. This review will highlight the synthetic strategies that have been reported for the covalent and noncovalent functionalization of carbon nanostructures with carbohydrates, as well as their applications in biosensing and biomedicine.