Abstract : Maturity-onset diabetes of the young (MODY) is a monogenic subtype of diabetes mellitus characterized by a young onset of type 2 diabetes, some abnormalities of the beta-cell function and an autosomal dominant inheritance with high penetrance. MODY types represent less than 5% of all cases of type 2 diabetes. Six genetic mutations have been described, one of them affecting the glucokinase gene (MODY 2) and the others various transcription factors HNF-1alpha, HNF-4alpha, HNF-1beta, IPF-1 and NeuroD (MODY 1,3,4,5,6, respectively). These different underlying gene mutations are associated with different clinical forms of the disease. Among the two most frequent forms, MODY 2 (mutation of the glucokinase gene) has a benign clinical evolution whereas MODY 3 (mutation of HNF-1alpha gene) has a much more severe evolution. The recognition of the MODY diabetes is important in clinical practice and may lead to the discovery of new more specific molecular therapeutic targets