Sphincter of Oddi dysfunction (SOD) has long been a controversial topic, starting with whether it even exists, as a sphincterotomy-responsive entity to treat, for either: (1) post-cholecystectomy abdominal pain and/or (2) idiopathic recurrent acute pancreatitis (IRAP). Many of its aspects had required further research to better prove or refute its existence and to provide proper recommendations for physicians to diagnose and treat this condition. Fortunately, there has been major advancement in our knowledge in several areas over the past few years. New studies on challenging the classification, exploring alternative diagnostic methods, and quantifying the role of sphincterotomy in treatment of SOD for post-cholecystectomy pain and for IRAP were recently published, including a randomized trial in each of the two areas. The goal of this paper is to review recent literature on selected important questions and to summarize the results of major trials in this field.