The advent of a pain free non-invasive technology would improve the patient’s compliance for regular blood glucose monitoring. Subsequently the diabetic patient’s life will improve considerably. Glucose monitoring is an integral part of diabetes management, and the maintenance of physiological blood glucose concentration is the only way for a diabetic to avoid life-threatening diabetic complications. Many reviews have already been published on this topic, but the great amount of information available and the fast development of technologies require a continuous update in the research status. This manuscript aims to review the various NGM techniques and devices.