The primary objective of this narrative review is to consolidate current mechanistic and preclinical insights into NGF/proNGF in diabetes-related complications and to define translational and clinical research priorities that can clarify the clinical relevance of NGF/proNGF as both a biomarker and a therapeutic target in managing diabetic neuropathy, retinopathy, cardiomyopathy, urogenital dysfunction and β cell function. This evidence concerns the gene NGF and diabetes mellitus.