Often underdiagnosed and sometimes falsely considered as a type 2 diabetes, type 3c diabetes (mostly known as pancreatogenic diabetes) is composed by a heterogenous group of illnesses characterized by diabetes mellitus associated with exocrine pancreatic insufficiency. The clinical, physiopathological and treatment features differ from type 2 diabetes, and they are important to keep in mind when diabetes is diagnosed, to avoid potential complications. The aim of this article is to review the principal etiologies of this often-unrecognized pathology.