Maturity Onset Diabetes of the Young (MODY), represents a rare cause of diabetes (1% of all cases), commonly misdiagnosed as Type 1 Diabetes (T1D) or Type 2 Diabetes (T2D). Clinical characteristics of MODY include age of onset before 45 years, absence of beta-cell autoimmunity and features of metabolic syndrome, sustained endogenous insulin production and strong family history. Common reasons for misdiagnosis are limitations in physicians' awareness and restrictions in performing genetic testing. In an attempt to improve diagnosis rates, recent research efforts have focused on the discovery of non-genetic biomarkers for prioritising individuals for genetic testing, with some promising progress (identification of high-sensitivity CRP, plasma glycan profile as HNF1A-MODY). The information provided is relevant to physicians dealing with young adults but details on pediatric populations are also included. Raising awareness about MODY and making the diagnosis more accessible will improve prognostication and management of these patients and their relatives.